iPhone Atlas reports on another Jailbreak method that has been published today -- this time from the iPhone Dev Team. Unlike the previously described method, this Jailbreak does not involve the use of the TIFF exploit, which is likely to be patched in a future update.
The process is described as "somewhat involved" but well documented. All files are available at:
http://conceitedsoftware.com/iphone/1.1.1-jailbreak.zip.
And involves the following process:
Downgrading to 1.0.2 (if you are already running 1.1.1)
Preparing the iPhone for a jailbroken update
Performing a software update, leaving you with a jailbroken v1.1.1
Forcing v1.1.1 to mount read-write so you can access it
Installing SSH and BSD world
Activating with a Non-ATT SIM (not necessary if you use AT&T)
Patching SpringBoard to allow third-party applications
Clean-up
At the end of this procedure, you should have a 3rd party app enabled iPhone 1.1.1. More streamlined techniques are likely to come, and users should proceed at their own risk at this early stage.