Easy to understand videos on many topics, especially web 2.0. These videos are embeddable and free. They can be used in training and for student tutorials.
Wiki site - one of the best, easiest to use wiki sites I've found. Education acounts are free and you get 10 mb of storage space. Wikis are great for collaboration- among staff, teacher-student, and student-student.
Microblogging site that could be used for quick communication between staff, easy updates on projects, relationship building with team members, or even teacher-student communication.