Steps To Jailbreak iPhone 4, iPhone 3GS or iPhone 3G On iOS 4.1 Using PwnageTool 4.1.2
iPhone Dev Team already released pwnage tool 4.1.2 with a little update of bug fixing.If you want to update and jailbreak your iPhone with iOS 4.1 follow the step step guideline which has given below.But remember if you are a new iPhone users read the article which has posted here before jailbreaking.