I’ve just made many additions to The Best Sites For Cooperative Learning Ideas list:

The Many Faces of Inductive Teaching and Learning

Here are some resources specifically on Project-Based Learning:

PBL-Online

PBL Checklist

LearnIT TeachIT

PBL Exemplary Projects

The Buck Institute For Education

If these resources aren’t enough for you, Cybraryman has even more…

Here are some more resources specifically on Problem-Based Learning:

Amphitheater Public Schools Problem-Based Learning Resources