Holy cow! I didn't expect to see
this thread.
So, at the risk of making this purely a House Rules thread, here are the fast basics of the Prestige Class. One of the obvious pre-reqquisites, of course, is that you have to have a phoenix sharing your soul; that doesn't make it exactly popular.
BAB: as per Wizard
Saves: good saves are Fort, Will; bad save is Ref.
Skill points: 2 pts per lvl. I'll have to find the class skills, as I don't remember them off the top of my head.
Lvl 1: Flame-touched (no control; your hair burns constantly as per a torch), Fury of rebirth (firestorm upon death), Skin afire (2 pt fire reduction); +1 caster lvl
Lvl 2: Natural armor +1, Screech of the phoenix (opponents within 30' slowed for one round, DC 13+charisma bonus), +1 caster lvl
Lvl 3: Flame-touched (can temporarily stop the flame), skin afire (5 pts fire damage reduction), prot vs evil added to spell list, +1 caster lvl
Lvl 4: Natural armor +2, gust of wind added to spell list, +1 caster lvl
Lvl 5: Flametouched (control), burning hands and polymorph self (bird only) added to spell list, +1 caster lvl
Lvl 6: Natural armor +3, fireball added to spell list, +1 caster lvl
Lvl 7: skin afire (10 pts), fly once/day, phoenix's wrath (involuntary fireball upon unconsciousness), +1 caster lvl
Lvl 8: Natural armor +4, flame-touched (mastery - burning eyes!), flame strike added to spell list, +1 caster lvl
Lvl 9: Skin afire (immune to fire), become an Outsider (with everything that entails), +1 caster level
Lvl 10: Natural armor +5, fire storm once per week, +1 caster level