I really didn't realize how limiting the old iPhone OS was until I upgraded to the new iOS4 on my iPhone 3Gs so here is the short scoop:
More as time allows, have you found any cool new things with your iPhone?
"Apple has just released the iOS 4 update for iPhone and iPod touch owners. The iPhone 4 might not be in stores until Thursday, but existing owners can take advantage of the new software features coming to the new device starting now."
- iOS 4 Update Has Arrived (view on Google Sidewiki)