I looked around and I didn't see a list of sites so I figured I'd start one with my current goto site:
http://gscentral.org/Edit::
www.cheatcc.com has been known to put up some as well, but I haven't been there in ages and I have no idea if it still exists.
GSCentral is run by a guy named Rune. From what I gathered, they all used to run GSCentral.com which had a much nicer layout but I guess everyone parted ways. He started GSCentral.org but then again, everybody parted ways so he revamped the site. You can't browse codes anymore but you can search them up for any game/system.
I had no idea there was this much drama behind finding little game genie codes for Zelda and pokemon games but apparently it's a full blown soap opera. Nevertheless, this Rune guy is pretty nice and they're a newb friendly site, meaning they won't call you a fag for having ten posts.
Anybody else have any?