Beguiler Questions

[BenShums]

I have a level 3 beguiler, with 20 Intelligence, which gives him a level 5,4,3, and 2 bonus spell, and two level 1 bonus spells (Player's handbook, page 8). Since he is level 3, his "Spells per day" list only gives him 6 level 0 spells, and 5 level 1 spells. Are the spells that a beguiler knows limited to the "spells per day" list, or is it limited to the spell levels he can cast? That is, can my beguiler at level 3 cast a level 5 spell, or is he stuck only to level 1 and 0 spells?

Also, I've selected Arcane Discipline and have chosen the Travel Domain. Can my Beguiler cast a Travel domain level 5 spell since he has a level 5 bonus slot? Or, at maximum, can he only cast a level 3 spell since he's 3rd level? Or, at maximum, can he only cast a level 1 spell since his "spells per day" list only gives him level 0 and 1 spells?

For his Advanced Learning spell (which I pick up at level 3), I'd like to have Net of Shadows, but I'm unsure of the rules. Here's a description of the spell: http://dndtools.eu/spells/magic-of-faerun--20/net-of-shadows--1701/ What is the Will Save used for? Because it's creating ordinary shadows, shouldn't that give 9/10ths concealment no matter what, regardless of will? If so, what is the Will Save used for? If not, how does a Will Save somehow improve an NPC's ability to see through the darkness? Also, does this spell work on undead?

Finally, can I use "heighten spell" on a level 1 spell to make it act like a level 5, taking up a level 5 slot that I should (theoretically) be getting from my 20 intelligence?

[Firebug]

From the SRD:
"The ability that governs bonus spells depends on what type of spellcaster your character is: Intelligence for wizards; Wisdom for clerics, druids, paladins, and rangers; or Charisma for sorcerers and bards. In addition to having a high ability score, a spellcaster must be of high enough class level to be able to cast spells of a given spell level."

"Divine spellcasters do not require spellbooks. However, such a character’s spell selection is limited to the spells on the list for his or her class. Clerics, druids, paladins, and rangers have separate spell lists. A cleric also has access to two domains determined during his character creation. Each domain gives him access to a domain spell at each spell level from 1st to 9th, as well as a special granted power. With access to two domain spells at each spell level—one from each of his two domains—a cleric must prepare, as an extra domain spell, one or the other each day for each level of spell he can cast. If a domain spell is not on the cleric spell list, it can be prepared only in a domain spell slot."

Underlines for emphasis. Essentially you don't have the extra spell slots until you are able to cast them from your class anyway. (there are some limited exceptions, but you aren't asking about those)

Net of Shadows allows a will save to completely negate being affected by the spell. It is an illusion, so if they make the save they can ignore it, but it can still affect other people. IE, you cast it on an ally and they make their save, the goblins don't make their save so the ally is 9/10s concealed from them.

TLDR: You can cast only 1st and 0th level spells as a level 3 Beguiler. If anyone makes a save that particular person ignores the net. You don't have a 5th level spell slot (yet) so you cannot heighten up to 5.

[BenShums]

So seeing an illusion isn't interacting with it, but touching an illusion or studying it is?

[Chronos]

It depends on the nature of the illusion. Talking with an illusory person might count as interaction, for instance, if there are responses going back and forth. And combat (or attempted combat) should almost always count as interaction.