Here's a gameplay video of the first area in Limbo, captured from the IGF showfloor at GDC. Gamespot has a new article about the award-winning platformer up on their site as well. More recorded footage of GDC attendees playing IGF games (and interviews) in the extended as I find them, but there's quite a few of those already up on GameVideos in the 'Recently Added Videos' section.

Monaco gameplay video

Edmund McMillen interview

Jamie Cheng interview, Shank trailer