Sorry, I didn't realize the Java emulator link wasn't obvious... What I was really getting at wasn't that Xarcade was doing anything illegal, but they were sending people to sites bundling ROMs with emulators, which seems kinda precarious for the MAME enthusiast world that XArcade relies upon. And, are hosting a distribution of MacMAME on their own server (Appears to be 0.97u1) and linking not to macmame.org, but www.emulation.net (which doesn't seem to be up tonight?).

Anyway, here's the link to the Java emulator that doesn't seem to have a license, and has a pretty lame "copyright" excuse on their about page ("the games are too old and obsolete in the sense that there is no market for them anymore")...
http://www.gagaplay.com/jemu2/

(FWIW - The legal xarcade bundling isn't any news to me as I actually won a copy of one of the packs in a contest a year or two ago.)