Update jailbroken iPhone

Hello, I just jailbroke and unlocked (T-Mobile) a used iPhone that I bought and I realized that there are some apps that can only be used in iOS version 4.1I need to know if updating my iPhone from 4.0.1 to 4.1 using iTunes will kill my iPhone or disable my unlock. And if that will, how can I update my iPhone?

it will just disable the hack, and i believe the jailbreak can only go to 4.0.1 right now

Which iPhone? ipodtouchfans.com has tons of resources on jailbreaking and unlocking. You could probably update your firmware without touching your baseband. I think 4.1 is jailbreak-able by greenpoison, limerain, or redsn0w.