This is not even from the iPhone Dev/Elite team, somebody else called GeoHot (or George Hotz ) is responsible. However, from what I read, this only describes how to downgrade an existing 1.1.3 phone to a lower version, but not how to keep it at 1.1.3 ‘unlocked’.
My iPhone is running 1.1.2 very well right now, so I think I’ll wait a little bit longer until there’s a good and complete guide to unlocking 1.1.3 and keeping it at the same level. Plus there is always the chance that one or another thing breaks or deletes keys/programs that are specific to your iphone.
There’s also supposedly another unlock possible from the iPhone Dev/Elite team, but they are keeping it secret until after the SDK is released. IF the SDK is released as scheduled for end of Januari, of course….