These days mobile devices are everywhere. One of the cool things about Windows Mobile devices (Smartphones and Pocket PCs among others) is that they can be programmed fairly easily using Visual Studio. Built in simulators allow for quick debugging without the need for an actual physical device. The big difference between programming for a mobile device and a standard PC though may just be the user interface design. The screen size is one obviously piece of that but there is also the differences in input – small keyboards, styluses, and no mice.
Recently Hilary Pike presented on the subject of mobile application design and then wrote about it on her blog. She posted her slide deck as well. I learned a lot from the blog post and associated deck.
I know a number of teachers who have their students create mobile applications after the AP CS exam (coming up on May 6th this year I think) for something different. This deck and blog post may be very useful if you are one of those. Or honestly for anyone thinking about creating their own mobile applications.
Oh and before I forget, Hilary also posted a bunch of links to sample Mobile applications here.