I went shopping with my MIL today, and picked up a couple books on spinnning and knitting from the Alta Vista branch. The Self Sufficient Living book gives detailed information on creating your own spinning wheel out of a bike. I think I might actually understand how a double treadle works with a flyer... I think I'll have to see it in action to really understand the whole "slipping" thing.
I think the Mainses own a spinning wheel. The next time we visit her, I might ask Nicki or Jennifer to show me how to spin :)