Jigsaw puzzles are great fun, but they're not exactly ideal for carrying around with you to play on the bus.
JIGaSAWrus makes it possible to play puzzles while you're on the move, via your Pocket PC. It comes with a selection of five pre-installed images that range from 104 to 204 pieces. The object of the game is, of course, to put the puzzle together in the minimum amount of time.
The great thing about JIGaSAWrus is that the puzzles are highly configurable. For example, you can set whether to allow rotational pieces, scatter pieces randomly, arrange pieces at the edge, etc. You can even import your own images and turn them into a jigsaw, making this a game with longevity.
On the downside, JIGaSAWrus isn't very user friendly, and it hasn't been designed very well with the small screen in mind. It's impossible to view the whole playing surface and all the pieces on the screen at once and instead you need to click and drag the screen to scroll around. There is a zoom tool but it only has two levels of zoom, so it's largely redundant.
If you're keen to play jigsaws on the move though, JIGaSAWrus is one of the most fully-featured Pocket PC versions you'll find.