http://moodle.org/ coming soon
Free Moodle Hosting (with Moodle pre-installed for you)
These are not really for real classes - they are too limited and slow for that, although you might get away with a small class.
Wallwisher Online notice board maker
Animoto Automatically produces beautifully orchestrated, completely unique video pieces from your photos, video clips and music (up to 30 seconds video for free)
Voicethread Known as a “group audio blog,” Voicethread allows users to record text and audio comments about uploaded images. (get a free VT educator account)
Screentoaster Free online screen recorder