Chris Riley, Policy Counsel for Free Press (and former EFF legal intern), has worked up an illuminating multi-part series of blog posts explaining some of the key issues that have been raised in the FCC's net neutrality proceedings (EFF's comments to the FCC echo many of the points discussed).
If you don't have time to dig through the huge volume of submissions piling up on the FCC's servers, his blog posts are a good place to start: