Ultimate MAME: Links
MAME The grand-daddy of them all.
LuSid's Page, Has an original Arcade Cabinet design that I roughly based mine on.
PC2JAMMA Excellent source for PC and Arcade Monitor connectivity.
Arcade@Home Great page for updates, ROM sources, news, etc.
Arcade Controls Excellent source for "How To" on building, or modifying your own Arcade Machine.
Hagstrom Electronics Great souce of comercial keyboard/trackball/spinner encoders.
HAPP Controls TONS of parts and supplies for arcade cabinets.
MAME World Another all around good source for MAME software.
Hanaho Comercial sales house of cabinets and Arcade PC's.
Mame.dk Lots of ROMs
Emulator Zone Lots of good emulators
Tombstone Project ROM site for order
CherryRoms.com for good SNES ROMs
Kefka's SNES ROMs