Warlock powers in 3.5

[Darg]

Sorcerers in 3.5 don't have the ability to learn directly from scrolls, in the base rules. Not anywhere I've seen.

These new spells can be common spells chosen from the sorcerer/wizard spell list (page 192), or they can be unusual spells that the sorcerer has gained some understanding of by study. For example, a sorcerer with a scroll or spellbook detailing an unusual sorcerer/wizard spell (one not on the sorcerer/wizard spell list in this book) could select that spell as one of his new spells for attaining a new level, provided that it is of the right spell level. The sorcerer can’t use this method of spell acquisition to learn spells at a faster rate, however.

With the DM’s permission, sorcerers and bards can also select the spells they gain from new and unusual spells that they have gained some understanding of (see Spells in the sorcerer description, page 54).

For instance, when Hennet the sorcerer becomes 2nd level, he gains an additional 0-level spell. He can pick that spell from the 0-level spells on the sorcerer and wizard spell list, or he might have learned an unusual spell from an arcane scroll or spellbook.

It's basically a thematic way for sorcerers and bards to learn spells not on the normal spell lists.