Nings, educational platforms, forums - everything related to professional development.

PYP Threads - Ning created by Kathy Epps to support collaboration within the PYP community

Educator's PLN - Ning created by Tomas Whitby

K-12 Online Conference - Ning created by Darren Kuropatwa

Future of Education - over 230 links with excellent interviews on education

Professional Development project - wonderful! It explores differentiated instruction, deeper learning etc.