1) Once you are using the latest version of Installer app (Version 3.0 beta), install Community Sources, then go to Sources at the bottom right, Click edit at the top right corner, and then click add at the top right corner and type in this url: http://markmon.mine.nu:90/iphone/repo/repo.plist. After adding it, hit Refresh at the top left. If you are using the old Installer 2.0, you can just enter the url in Safari.
2) Find and install BSD Subsystem and then Anysim 1.1.
3) For the time being, go to settings, general, and turn off Auto-Lock.
4) Run the the app, slide, and read the directions. After a few minutes, your phone should be unlocked!