This looks like a LOT of fun and not too pricey

Carnegie Mellon University announced on Wednesday an initiative to help people make a robot that connects wirelessly to the Internet. The Telepresence Robot Kit, which consists mainly of a free set of directions and a recommended robot controller run on Linux, was developed over the past year and a half by Illah Nourbakhsh, an associate professor of robotics at the university's Community Robotics, Education and Technology Empowerment Lab. The project was done with financial support from Google, Intel and Microsoft.

photos & info:
http://content.techrepublic.com.com/2346-3513_11-63952.html

actual site is at:
http://www.terk.ri.cmu.edu/recipes/index.php