I have set up my Droid X via Wifi to hook up to my Windows 7 PC through DLNA. It's been working brilliantly
On the PC side all the settings are in Windows Media Player. Basically need to enable streaming within your network, and if you want allow the phone to control your PC. It all works as advertised, all over wifi. All those years in a Windows Mobile Phone wishing I could update my phone over wifii with active sync. It's a reality now, as long as my PC is on.
The Droid X even has a setting specifically for the Xbox. Would rather try this with a PS3 but I have neither. Seems like you could control any of these devices from anywhere your wifi reaches with just your cell phone. I have been using it to transfer music to the phone over wifi. Great stuff, but obviously you may have to open yourself up a little bit on your network. Oh lastly, just have an old Athlon 64X2 nothing special. Using a WRT54GL router flashed with one of the popular firmware whose name escapes me at the moment. No real special settings there either as far as I can remember.
Oh and I do not have a TV to try this out on but supposedly I could play a video from my PC to my TV all while controlling it on my phone...over wifi. Basically from any device to any other device as long as they have DLNA.