[Update] Aug/25th/2008: read here, everything you gotta know about Proxy SIM solutions.
The Bladox Team has released an application for their Turbo SIM (see here how proxy SIMs work) that is obviously able to bypass the SIM lock of 3G iPhones – means unlocking it. The application is still beta and might not work on the entire planet, but it obviously does in the U.K. The name of the app is zerog-0.95.tar.gz, but for legal reasons we will not directly link it.
See this video:
It takes ages until it is logged it, but anyway it documents the current status quite well…