Many web-based programs exist to enhance teacher-student interactions. Here are links to several that you might wish to explore.
Schoolnotes
http://www.schoolnotes.com
Eboard
http://www.eboard.com/
Google Groups:
http://groups.google.com/intl/en/googlegroups/about.html
Yahoo Groups
http://groups.yahoo.com/
Example: Charles Burrows, Spring Valley HS, NY