Where to find Fixes?
Renegade's page is a must for new and unofficial drivers. Since he is able to update more often than me, I will leave what I have here just for training purposes and you should look there for the most up to date stuff.
Steph, from the Ultimate Patchers has a few fixes from time to time
The various message boards get fixes and updates all the time, so look around!
Other Places of Interest
MameWorld! - THE place to go for everything that is MAME. Links, help pages, tons of hosted sites (including this one), and a few forums.
The official MAME home page needs no introduction.
The MAME32 QA, art, and testing department is a must for Mame32 users.
MAMU's Icons - In my opinion, he has the best icons available.
RETROGAMES - Is a great place for Emulation news and links
VG-Network - Is also a good place for news and links
EMU-ZONE - Same as the other two with a few goodies that the others don't usually advertise