http://www.classicgaming.com/mame32qa/
For the latest and greatest version of MAME32
http://www.kaillera.com/
Online play with Mame
http://retroroms.foreverchat.net/
For pretty much every single rom for MAME including the CHD's
I also have Metal Slug 5, Samurai Shodown 5, and SNK vs. Capcom roms if any one wants them.