Here's a politics column from Slate on John Edwards talking about issues and indirectly criticizing Obama for not talking about them. But, all the candidates need to start talking more about policy I think.
Obama's website has a nice section on issues with a good interface for people to provide input. I thought that the discussion on the pages was a bit too much, here's a list of legislation that I supported and a bit too little about what he would do as President, but maybe it's early yet.
I still would like to see something like my suggestion for a policy comparison website (see previous post).