Do it again, and again until you stop feeling remorse?
Seriously. After a while, it becomes more of a habit than a secret. If you need to to graduate, you don't gain the full benefit, but you guarantee graduation.
Test cheating isn't really a huge deal unless you're doing it on a college entrance exam, in which case you'd be robbing people of an opportunity to get into their career path.
>>3 Hey bro, shit happens. Don't worry about cheating on a test or two. Just relax, sometimes people aren't ready for a test, and fuck, I'd much rather cheat than fail. You know? Just chill, its not like you're committing murder or adultery.
Don't worry there will be much more things in life you'll do that brings a much greater deal of guilt. Just have a laugh and forget about it, make sure to not cheat again though :)
Cheating on a test kind of prepares you for the real world. A place where sometimes the rules need to bend a little if you want to get anywhere. Stop feeling guilty. Congratulations, you're doing just fine.