iPhone: Downgrade from iOS 4 to iOS 3.1.3

I have red many people commented on different websites that their iPhone 3G (S) has slowed down after upgrading from iOS 3.1.3 to iOS 4. While surfing over the internet i found a really good post which will help you guys to get rid of iOS 4 and you can downgrade your device to previous iOS. Follow the LINK for detail steps of downgrading your phone. This will really help you.

Let us know whether it worked for you or not?