In general, any well-known glitches (in World of Warcraft they’re usually referred to as ‘exploits’) are usually addressed by the Development Team in the next patch. Or, if the exploit is serious enough, the Devs will sometimes implement a hot fix, which is basically a mini-patch that they implement immediately instead of waiting for regularly scheduled maintenance (which in WoW happens on Tuesdays). So, basically the best you can really hope for is to find a collection of old glitches because any new ones will likely be remedied quickly.
As far as cheat codes, MMORPGs aren’t really the kind of game that includes that sort of thing. In any event, if you were somehow magically able to pull high-level gear from thin air without raiding or grinding for money, it would probably bring the eyes of the Game Masters on you very quickly and you’d likely be facing penalties that could range from a stern conversation concerning the ‘spirit of the game’ to a permanent ban of your account. (This also applies to exploits, mentioned above).

There are really no cheat codes when it comes to World of Warcraft because it is an MMORPG. There are really no remaining major glitches that haven't been fixed by Blizzard's development team. Therefore, when it comes down to it, the best bets for getting anything remotely like a cheat is to use sites like wowhead which provide you with information on quests, items and people, monsters and animals in the world. They have user tips which can greatly enhance your gameplay. There is also thottbot if you prefer it over wowhead which I do not.

The Curse client also allows you to have add-ons and easily manage them. These can make the game easier and make completing quests and achievements faster and much easier than it is without the add-ons but they do take away from some of the challenge and at times can slow down the game.

www.wowhead.com
www.curse.com