John Boiles, a software engineer, has just finished making his really cool WiFi RC car that uses a Linksys router (attached to the RC car) and his iPod Touch as control. You can learn how to make one of these awesome iPod Touch controlled WiFi RC Cars here.
I don’t want to take anything away from John but a little suggestion, instead of mounting the whole Linksys router, you might do better using a WiFi module for embedded processors. (or just strip the plastic off Linksys at least)
Brilliant project though, making use of WiFi is ideal I think due to its range, add a WiFi repeater and go even further.