Sub-$500 robot made from open hardware and free software

I am bored, tired of waiting for a future filled with robots that never appears, so I decided to create a robot and help advance the technology to the point where robots may one day become commonplace in our everyday lives. My goals are to create a general purpose robot that i can control via the internet and communicate with the real world. it will most definitely run linux and will be pretty small. the requirements are for it to be able to drive pretty much anywhere @ ISU. this includes sidewalks, buildings, grass and such. since it is going to be controlled via the internets, it will have to have some way of recording what its going on around it. a webcam would be perfect for this. additionally, it will have to be able to send messages to the people around it. this will require either speakers or a display. speakers would be the easiest and least power hungry.