you could use an airport express, which will connect to your wireless network. it has an optical out which you can hook into your receiver. itunes will show the airport express as a speaker that you can select instead of your computer speaker. so then you can use your computer to control itunes, or if you have an iphone you can use the remote app.
note that in my experience, the airport express is extremely buggy and has a lot of interference especially with overlapping wifi networks, but it's the best solution i've found...