Some quick EACHing:

Wasp
No major comments. Looks really well done. The only quibble I have is with the entry requirements. 60 skill points is a large number of skill points for requirements even if it is intended for rogue entry. If a rogue has say +4 to int then they would have when they enter this a total of 144 skill points, so a little under half their skill points have to be put in to it. That may be ok, since they are all useful skills which are useful for rogues and are useful for Wasps. I'm not sure here.

Sneaky Hand
If I'm reading this correctly, a sufficiently smart wizard can enter this class at level 4, and wizard 3/rogue 1 can then enter at level 5. Normally PrCs are supposed to be harder to enter that early. Frankly, I'm fine with PrCs being easy to enter early (and think that making so few with low level entries is a major design flaw of 3.5 since most games end well before 20th level and unless one is in a setting like Forgotten Realms, a 6th level character can be very reasonably prestigious), so I'm more curious if this is intended to have such early entry. I don't think any of the basic class features are an issue if one is entering early.

Is there an issue with the "I Like This!" ability to be abused? Say PCs find an object of unknown nature. One of them puts in their pocket, knowing the Sneaky Hand PC will go and pull it out to identify it. Depending on how this is played, this could either be seen as abuse of the class feature, humorous, or breaking versimilitude. I'm not sure what to do since the feature is a fun one and makes me want to play a Sneaky Hand just for the regular use of this ability.

For the class feature Easy Casting it reads: "At 2nd level a Sneaky Hand cast some spells in light armor without invoking the normal arcane spell failure chance." which spells?

They never saw it coming is interesting but maybe a little too powerful? It also has two typos ("slight" and "wit"). I'd suggest a slightly weaker version as follows: "At 2nd level a Sneaky Hand has become so good at pick pocketing that only other pickpockets can realize that they are being pick pocketed. When you use sleight of hand your opponent takes a -5 penalty to their spot check unless they have at least 4 ranks in Sleight of Hand."

In Soul Stealing "any feats" should have a capitalized any. I'm not completely clear on what can be stolen if one can steal spellcasting like this, since spellcasting is normally written not as its own (ex) or (su) ability but has its own entry. Also, being able to steal spellcasting this way seems potentially overpowered. The idea behind the ability is really neat but more details are needed.

Hedge Mage
I really, really, like this PrC. Everything about it is well done, and it looks balanced even given the massive set of spells they can cast.
Entry requirements- The special requirement is a little ambiguous. If for example a sorcerer can only cast first and zeroth level spells and they then fail a will save against a second level spell, but then gain the ability to cast 2nd level spells and then fail a reflex save and a fort save against a 4th level spell, do they qualify?

Expanded Spell Knowledge- The ability is really cool. I could see this leading to problems with splatbook diving. It might make sense to have a note to DMs that if a PC is going to play a Hedge Mage then they should discuss with the DM before hand to make sure that they don't drastically slow down combat by spending forever thinking about what spell they are going to cast.
Also, the note on Expanded Spell Knowledge seems to have a minor formatting error with an extra italic close at the end.

Gutter Instincts is all good but "tus" should be "thus" I think.

Openminded refers to the class as "witch" (I'm guessing this was from an earlier draft). Also "ofr" should be "of" I think. I'm not sure what you mean by "and if such an effect would still affect her (Such as Dark Speech) it instead has no effect"- can you clarify?

Spell Transfusion- "Tey" should be "they" I think. This seems a bit powerful but for fourth level and lower spells seems ok. My guess is that this is not intended to remove spell components (V,S,M, etc.) but if so that should be stated explicitly since supernatural abilities don't have them. If it is intended to remove them, then this may be unbalanced.

Spell Chain- Says witch when you mean Hedge Mage.

Epic Hedgmage- This looks not complete yet, although most of it seems self-explanatory from the table.

Minimizer
Class idea is interesting. Definitely needs clarification on what abilities are (ex), which are (su) and which are (sp) since it isn't obvious for some of them. The entry requirement seems onerous. Yes, the Swiftblade has a similar thing, but using every single spell slot that way is tough. I'd suggest just requiring the ability to cast Reduce Person and make the special requirement that one has used it offensively in combat.


Dust Devil
I take it this used the desiccation rules from Sandstorm? If so, I'd state that explicitly as a note so there's no confusion. It isn't exactly the most well known splatbook.
My initial reaction was that the entry requirements were too high but given the power of the 4th and 5th level abilities, requiring 5th level spells seems about right. Overall, I like this PrC and it feels like it is one that should have been in Sandstorm in the first place(that is intended as high praise this uses the mechanics so naturally it seems like it should have been there all a long.)

Master of Needles
This PrC immediately brings to mind a certain scene in Crouching Tiger, Hidden Dragon (you probably know what I'm talking about).
One thing that jumps out is that this class is easier for a fighter to qualify for than a monk. This seems odd. I'd suggest in the entry requirements either BAB +6 or 5 levels in Monk.
One other thing I'd suggest is that they should at some point get a bonus to confirm critical hits with their needles- Maybe at level 1 they also add their class level to rolls to confirm critical hits?

Leveler
Well, for starters the picture and poem fit very well, and apparently Shelly's middle name was "Bysshe" which I didn't know, so yay. The central class feature is well done, and a lot of work clearly went into the spells and balancing them out. My only quibble is the name: given the fluff about leveling everything and point of the Shelly poem being how everything ultimately comes to naught, calling their central ability "elite spellcasting" seems odd. Unfortunately, I don't have a better name.

It might be nice also to give a few class features that let you explicitly damage buildings and structures more easily. They don't need to be strong (the class itself is pretty strong already) but it might help fit the theme a bit.

Hive Master

The first three levels seems to have fit its primary goals of being a non-evil hive focused class that is reasonably balanced. Bravo. There's something marked as "Special" in the last level in the table that doesn't seem to be explained in the PrC?


Singer of the Forbidden Song
Entry requirements Is this really evil? It seems like a non-good alignment restriction would make more sense. And Zazu seemed lawful good or lawful neutral in alignment (ok I know that part isn't serious).

Selective Hearing is a really good ability here to make this PrC playable. Is Selective Hearing and Debilitating Song also (ex) like the song itself? If so, that should be mentioned. (Also the ex-bard abilities should also have their type clarified). Overall, seems like a balanced and fun PrC that would be fun to play.

Mini-o-Mancer
This is hilarious.
"Rebuke Tiny Beings" I get that the class level rule is there for obvious reasons, but it would be pretty funny if they could actually order around even beings with *tiny* numbers of class levels. Maybe it should work on beings who have fewer class levels than half your number of levels in Minoi-o-Mancer?
Most of the class looks well balanced (I don't know the gramarie system well enough to comment on the option associated to that but the others seem fine.)

Dermagraphter
Ok, this is icky, and gross and creepy and I love it.

The Flay tatoos ability when they are applied to class features needs a little more clarification. Are these changes permanent? How would someone who has had them removed go about getting them back? Does the ability work on a Green Star Adept or Acolyte of the Skin of 10th level where the effect in question is explcitly throughout their body? I think more clarification is needed.