i rooted my motorola droid and now i want to go back to unrooted how do i do this HELP ME PLEASE?

i rooted my moto droid a little bit ago it now has android 2.2 build FRG22. it slowed down my phone and doesnt let me use some things like the navigation and the camera is a little wierd now. is there anyway to completely wipe the entire phone of everything and make it literally like it was out of the box. i dont want to have a rom that gives me android 2.1 i want the legit android 2.1 .... i just want to undo everything i did. how can i do this thanks for any help you can give

Read more here ...