We are doing just that, we have the Network Camera, and router. Have you guys ever done anything like this before? If so I would love to get some help! Thank You! (on the programming part not building, we already have the robot built)
Wow, thats amazing. Not to mention a good idea!
Though our team has never done anything quite to this extent, I could foresee a few relatively simple ways to go about doing it.
I would be interested to know exactly what kind of robot you’re talking about controlling though. Got any pictures? they would be useful to anyone trying to give advice.
I think I might just play around with a concept like this now in my free time. 
CD User ChrisSanborn had a very similar idea a while back. Although it appears to be down now, it worked excellently at the time, and he’d probably be the go-to guy for some suggestions/pointers.
You could try a PINK module.
http://www.parallax.com/detail.asp?product_id=30013
http://www.makezine.com/blog/archive/2006/12/control_a_web_e.html
http://www.instructables.com/id/Garage-Monitor-3k/
Microchip has a ethernet interface chip (ENC28J60). It’ll do you right, but it’ll take a bit of gumption to get it working.
Use the Pictail so you don’t have to spin a custom board.
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en027750
Alternatively, put a gumstix in there. It’ll put you back a little bit more in terms of $$, AND you’ll have to learn a new environment. However, it also has a bit more kick to it.
Good luck, and let us know how it turns out!