Do NOT do unto others that which you would NOT want done unto you.
Steer clear of the oversimplified translations, dudes.
Actually it is stated both as (paraphrasing because I don't want to look up verses for exact text right now) "Do not do to others what you would not want done to yourself" - at least once and maybe twice in the Old Testament law - and "Do unto others as you would have them do unto you" - in Matthew during the Sermon on the Mount. Both kinda amount to the same thing really. And, as I said, there is some variant on the same theme in most religions. Have a look at the Wikipedia page for "The Golden Rule" sometime to see it stated several other ways in the texts of several other religions.