Update Your iPhone To iOS 4

Links after the break.

Apple released the iOS 4 for the iPhone this week. The update enables multitasking, app folders, iBooks, improved Mail client, spell-checking, and other improvements. Multitasking support is not included with the 3G model. The 2G model cannot update to iOS 4.

Make sure to install the latest version (9.2) of iTunes before updating to iOS 4. It will not be compatible with earlier versions of iTunes. You can download iOS 4 on the links below.

For 3GS model

http://appldnld.apple.com.edgesuite.net/content.info.apple.com/iPhone4/061-7437.20100621.5urG8/iPhone2,1_4.0_8A293_Restore.ipsw

For 3G model

http://appldnld.apple.com.edgesuite.net/content.info.apple.com/iPhone4/061-7436.20100621.58Yt4/iPhone1,2_4.0_8A293_Restore.ipsw