Need to get rid of update 3.1

[Safnerd]

So i have the 3.1 update for my iPhone and since I did it I have been having a lot of problems with random shut downs or freezes.
Like the phone will just not do anything until I reset it. Won't read in a comp, power change, etc.

So I saw that you can fix it by getting rid of 3.1 and go back to 3.0.

Only question is how do I do this? i wouldn't know where to start. D:

[spillproof]

If you have a 3G it is possible. 3GS not so much.

This method (http://forums.macrumors.com/showpost.php?p=8502006&postcount=2) had been know to work for 3G if you have a Mac.