As we all know Launchpad in Lion behaves like iOS on our iPhone and iPad devices.
To create and organize folders on your Mac using Launchpad, open Launchpad then hold down the Option key and while your apps are shaking you can create and organize them to desired folders.
Just makes it easy, hope you find the tip helpful.
[crarko adds: This points up a divide we may see amongst Mac users; if you use iOS something like this feels natural to do, and obvious. If you don't use iOS, I imagine this behavior is a bit odd, and you may not think of it. I still have reservations about the mixed metaphors of Lion, although fortunately none of them are required to make good use of the system.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20111018010438408