Your phone is unlocked when you unlock it? Yanno? You would know if it was unlocked. You flash it to a different carrier by following guides and stuff. If you are asking about your EVO, good luck. Only carrier I know it would work on other than Sprint is Cricket another CDMA carrier.
That other thread wasn't targeted towards you, it was for the really inactive people. LOL. Once you update your review, let me know though :)