the idea of controlling a robot through phone lines falls into a general category of telerobotic..other related branch would be teleoperation, telemanipulation and haptics..google out and u'll find many interesting links..
There are some very good projects in robotics.
Why don't you try building a micromouse.
It is an international competition and you can find many sites that give away information on micromouse. You could also contact the other teams who have build such mice and you can get some tips from them too.