YW - I think the key to the network is having the Apple brand router, called Airport Express or Airport Extreme. No other type of router will work (including my NetGear router). Also, the Apple brand external hard drive, called Timecapsule will awaken if it's on the home network (with an Apple branded router and Mac of course), good for if your internal hard drive is full and you want to move your media to an external drive.
It's a case where in order for us to have this great feature of having ATV wake iTunes, we need to have Apple's Airport type router and an Apple Mac. The computer can be hardwired w/Ethernet cable to the Airport Express router, so you're ok there if you don't need a wireless Mac. Check the Apple store it sells the Aiport routers (kinda expensive but I'm sure the quality is top notch).
http://store.apple.com/us/product/MB321/AirPort-Express-AirTunes
If you get that then you should be good to go!