iTunes on the road is what it's all about, for those w/out an iPod, check out my quick howto on getting your tiBook mounted under the dash in your car:
Good idea bret, the only thing I'd be worried about would be the Tibook sliding out of the rack somehow...other than that, it looks good to go. I've thought about this, but I always just envisioned putting in the seat next to me (with something to block it from moving forward) so I could reach over and toggle playlists and such. You seem to have a nice setup there...enjoy the roadtrip