All the core, base, alternate, and prestige classes from the SRD will be allowed, see http://www.d20pfsrd.com/classes.  If you want to take levels in a class from a third-party product or a 3.5 edition source, let's sit down and look it over to make sure it's not over or under powered, or a game breaker.  I will permit most most options, but reserve the right to do some tweaking if there are issues.

As stated on the Races page, I will be revamping Race levels, Monster levels, Template levels, and Undead levels for PC use.  If you have something you are considering, let me know so I can get that ready and discuss it with you.

I have the playtest copy of the Advanced Class guide, but haven't read it yet.  If you are excited about options from there please let me know so I can get familiar with the new rules.