Alright, I've read quite a bit about jailbreaking the 3G now... but one question still worries me:

If I jailbroke my 3G FW 2.2 now, what would happen when FW 2.3 is released?
Can I just upgrade the jailbroken FW 2.2 with a "clean" 2.3, or do I have to restore the iPhone first or would it even be impossible to upgrade the FW unless there would be a new jailbreak?

Point is: It's a contract phone, and I don't want to wake up one day having a useless phone while still having to pay the contract.

Replies would be much appreciated as I would love to hear that everything was okay and that I could start jailbreaking it right away.