I've used an Airport Express for many years, first via WiFi then wired to ensure no dropouts.
Mac computer with iTunes > Airport Extreme Router > Airport Express > Onkyo TX-SR875 AV Receiver & Floorstander speakers.
The computer can be a PC, the router does not have to be from Apple, but the essential component is the Airport Express. Which for £83 is cheap!
www.apple.com/uk/airportexpress/features/airplay.html
You can then use your iPod/iPhone/iPad as a fantastic remote via WiFi using the Remote app from the iTunes App store.
Personally I plan to get an AppleTV device next as it can perform the same functions as the Airport Express but includes video.
Hope this helps.
TnA