How to unlock and factory reset a iphone 4s i found a year ago?

The phone has a 4 digit passcode and i do not know the passcode is there a way i can get through the passcode without entering.it? Id also like to factory reset the phone.

If you want your phone unlocked the best website to go to is http://unlocksphone.webs.com/ I honestly believe they have the cheapest unlocks