Telannia FOR SURE and I agree @deangroom is a good one. He's also host of a Diigo pbl resource sharing site - another good place to find out what pbl'ers are paying attention to: http://groups.diigo.com/group/projectbasedlearning. I joined and use this ALL THE TIME.
Oh and has anyone said David Warlick @dwarlick yet? I like following tweeting edubloggers like David because they announce on twitter when they've posted something new on their blogs. (Suzie and I do this too.) In that spirit I also suggest Neil Stephenson @Neilstephenson and Chris Lehmann @chrislehmann.