Site for connecting with, finding, and setting up opportunities to collaborate with others all over the world.
Secure blogging platform for teachers and students. Not as flexible in the way it looks, but VERY functional and VERY secure. Teachers have absolute control over who can/cannot see content. Ability to open up to the whole world or only restrict to blog authors. Account creation and login is also a snap. Check with your district.
Wiki from 2009 Learning@School conference. Contains lots of great collaborative tools and ideas for using collaboration in the classroom.
Use this tool to allow people to book times on your Google Calendar.
Prezi sharing different tools to use in collaboration.
Resources from Josh Allen for connecting with other teachers and classrooms.
Work together with educators from all over the world to develop a collaborative project. Online course.