I wanted to know the same thing, so I did a search of the forums and found this thread.
Forums at Splitcoaststampers
I used the directions from that thread and also read the article in April's Stampin' Success (nearly the last page) for ideas on how to do this.
Beware though. . . . .
you'll be hooked after you do just one! LOL!
I did them at my w/s on Wednesday and everyone loved them. One of my gals decided to use the idea to design her baby announcements.
Edited to add: the link goes to one of the demo boards, so if you aren't a member you won't be able to access the link. Sorry.