Last DFU Tool, which is used to put your iPhone 3G running on iOS 3.0 or iOS 4.1 in DFU(Device Firmware Update) mode without having to press the power/sleep button, has been released by iPhoDroid Team.
Note:It Only support iPhone 3G running on iOS 3.0 or iOS 4.1 and It might having Bugs as its the BETA version (Only for MAC Users)
How to enter into DFU mode using Last DFU?
Steps 1: Plug the iPhone with your computer.
Steps 2:Launch iPhoDroid Last DFU.
Steps 3: Tap Get into enter into DFU Mode.
How to exit from DFU mode using Last DFU?
Steps 1: Plug the iPhone with your computer (Skip if already connected).
Steps 2:Launch iPhoDroid Last DFU (Skip if tool is already launched).
Steps 3: Tap Get Outto exit from DFU Mode.
Download Last DFU from iPhoDroid
http://mrreg.com/_site.iphodroid.com/labs/2011/02/Last_DFU_3G_Mac_R1.zip
Unique Destination for anything Apple, and GizmOs » Enter into DFU Mode of iPhone 3G running on iOS 3.0 or iOS 4.1 Without Having To Press Power/Sleep Button
Note:It Only support iPhone 3G running on iOS 3.0 or iOS 4.1 and It might having Bugs as its the BETA version (Only for MAC Users)

How to enter into DFU mode using Last DFU?
Steps 1: Plug the iPhone with your computer.
Steps 2:Launch iPhoDroid Last DFU.
Steps 3: Tap Get into enter into DFU Mode.
How to exit from DFU mode using Last DFU?
Steps 1: Plug the iPhone with your computer (Skip if already connected).
Steps 2:Launch iPhoDroid Last DFU (Skip if tool is already launched).
Steps 3: Tap Get Outto exit from DFU Mode.
Download Last DFU from iPhoDroid
http://mrreg.com/_site.iphodroid.com/labs/2011/02/Last_DFU_3G_Mac_R1.zip
Unique Destination for anything Apple, and GizmOs » Enter into DFU Mode of iPhone 3G running on iOS 3.0 or iOS 4.1 Without Having To Press Power/Sleep Button