Thanks for all the advice. I'll read the reviews that you linked me to. It is sounding more and more like Player's Guide to Wizard's Bards and Sorcerers wouldn't be the best buy as far as total content. However, I really want to look at the prestige classes in there. I have heard good things about Blessed of Mesos and Angel Blooded. Is there any legal way to find enough out about just those prestige classes without buying the book? I am guessing not. However I would like there to be more relevant content in the book rather than just one prestige class. If only there was a way to buy just those few pages of the book.
Also, as far as my DM goes... he is pretty open to using anything as long as he can see the source material. As long as it doesn't sound too broken. I am guessing that if something became too unbalancing that he would just modify it later, or compensate by giving the other players specific items and limiting the party treasure... or something.
EDIT: I just read the review for a Player's Guide to Wizards, Bards, and Sorcerers and I have decided against it. The Blessed of Mesos sounds very cool, but if I was the DM I wouldn't allow it. It gives several extra things without taking anything away from the sorcerer. And the base sorcerer already isn't underpowered at high levels.