Where broad agreement exists, I've omitted the issue to save space. I've also omitted issues where one candidate has no stated position I could find, even though this is a measure of a candidate's relative concern for and familiarity with issues.
The main sources are the candidates' own websites, plus a whole lot of searching via Google. I can't promise every detail is correct; this is one guy's best effort.
Full disclosure: I have several friends on the Kucinich campaign, and I supported him when this started. A few months ago, I was even going to join up, but since I'm in the media, decided it was better to be independent.
I was also very interested in Dean for a while, around February and March, until I decided to support Kucinich.
Make of that whatever you will.
Finally, Dean is basically a good guy, and if he's nominated I'll vote for him in a heartbeat. It's just that it's simply not accurate to refer to him as a progressive candidate. As he told Salon: "I don't mind being characterized as 'liberal' -- I just don't happen to think it's true." I'm also not saying that Kucinich's positions are the "right" ones on every issue;
I just personally agree with him on most of them, and I think other progressives will, too.
PS: I had not the slightest idea how many people would visit this page. According to Memeufacture, a link here from TalkLeft quickly spread all over the liberal blogosphere. Thanks, cool, great -- but I'm not an expert, just a guy trying to figure this out. I've tried to correct any mistakes brought to my attention, but I do make them. Do your own research and thinking.
Table is at http://www.bobharris.com/kucinichdean.html