There's 3 programs you will need for this besides SCAL & Windows
1. A 3d creating software - A Free one is Google Sketch
2. Pepkura Designer - Free to Unfold your design and Print a Vectored PDF
3. Cute PDF Writer - Free Virtual Printer so you can import the Vectored PDF into Sure Cuts A Lot.
Part 1 - Design in Sketch Up
http://www.youtube.com/watch?v=oCuS6IReMXg
Part 2 - Have Pepakura unfold your creation and export to PDF
http://www.youtube.com/watch?v=iyZuyPvZxUw
Part 3 - Import into Sure Cuts A Lot
http://www.youtube.com/watch?v=Fbp4hHPB7c0
I did put closed captions on all these videos... You're more than welcome to repost these videos anywhere you like. Sorry for the links I couldn't figure out how to embed the videos on this post.