I found a jigsaw puzzle over at flightsim.com. While this one doesn't allow you to save and finish later I thought I'd pass it on:
http://www.simviation.com/yabbuploads/Jigsaw120709.jpg
When I double-checked the location of the file, I googled it and found this:
http://www.netspeed.com.au/bhk/puzzles_air.htm
Check out the other links at the top of the page
