Since I teach both piano and guitar, I'm always on the lookout for new resources online for both piano and guitar - or either.
This past week I've come across three different websites that I've found interesting.
Classical Guitar Review - has some great resources and exercises
Classical Guitar Corner - has some good exercises and good information to help with improving your skills
Anton Emery Celtic Guitar - Anton's blog has some good information on fingerstyle guitar playing, especially for Celtic music