1.) Reinstall iTunes using these guides: Windows XP: http://support.apple.com/kb/ht1925 Mac OSX: http://support.apple.com/kb/ht1224 2.) Update to 4.0.1 by using THESE .ipsw packages: http://www.quickpwn.com/2010/07/ios...le-for-iphone-4-iphone-3gs-and-iphone-3g.html 3.) Restart your computer. 4.) Once downloaded, click the restore/update button while holding ctrl (Windows) or option (OSX) and then select the downloaded .ipsw package. 5.) Wait for phone to update. This has worked for many people (myself included), who had their iPhones bricked from using their current installation of iTunes and the .ipsw downloaded automatically through iTunes.