Great app for having students create an educational product. I know Apple says it's a business app, but it has the kinds of multi-media tool compilation that makes for great education tool.  Students can easily capture/create an image on the iPod, annotate or draw on it while they narrate, and most importantly of all students can then email it to the teacher.  Not only can they create, they can share!  Katherine Burdick shared this on the iPod discussion in Classroom 2.0.

simple java based apps that can be used with IWBs 

Easy game to play in which students have to use their understanding of fractions to fill in gaps.