DraftWesleyClark.com had Zogby do a poll for them. Here's the press release and here's a link to the full .pdf poll analysis.
Some of it is a bit rigged - some questions are asked after providing bio info, which is pretty stacked in Clark's favor.
But, the most interesting are the Dem candidate matchups. Dean's at 16.6%, Gephardt's at 11, Lieberman's at 10.1, Kerry's at 9.4, Clark gets 4.9, and then there's the rest of the gang.