Geotagging is not only informative and educational, it can be fun. Kids really do love maps and when you combine the idea of pictures into them it can be even more interesting. I read a great blog post from Educational Technology - ICT in Education on geotagging with links to sites that can help classroom teachers get started.
Web 2.o for Rookies: Geotagging
Take a look and explore a bit. This is applicable to a wide variety of curriculum areas!