A day early? It was announced for June 21st
So far, iOS 4.0 is pretty great. I'm loving how the home screen backgrounds and the 3D dock are making my iPod look.
As for the folders, I brought my iPod down from 9 home screens to just 3

As for multitasking, well not many apps have taken advantage of it yet (at least not the ones I have) but hopefully they all jump aboard soon enough!)