What's the topic? Here are some resources

UC Berkeley Webcast/Courses http://webcast.berkeley.edu/courses.php

MIT's OpenCourseWare http://ocw.mit.edu/index.htm

Mozilla's School of Webcraft http://p2pu.org/en/schools/school-of-webcraft/

Google Code University http://code.google.com/edu/courses.html

Khan Academy http://www.khanacademy.org/

Ontwik http://ontwik.com/

Code School http://www.codeschool.com/

There are also a lot of startups focusing on tutoring&co, like

http://www.skillshare.com/

http://edufire.com/

http://www.tutorspree.com/

http://www.udemy.com/