Now that Apple has released iPhone OS 3.0, The Dev-Team can now release the jailbrake for the new firmware. There is 
already a jailbrake for the beta’s of the new firmware but it’s not advised you use it, as it could have cause some problems.
The release is said to be shortly after the release of the firmware so keep your eyes on here and I will post when it’s been released with download links.
Just a note to those who jailbrake not all the Cydia/Icy app’s will work on 3.0 yet so don’t expect all of them to work straight away.
Also on friday, the Dev-Team will be releasing ultrasn0w which will allow you to unlock the new firmware.
Sam's Blog 