There are several receivers that offer WiFi connectivity, however I do believe you're limited to 16-bit.

The Denon AVR-4810CI for example offers full WiFi Network Streaming.

Denon Canada's product page - http://ca.denon.com/ProductDetails/3534.asp

I believe you may need to special order this as it's above the price line for receivers that Future Shop normally carry.

I am not sure of any other way to do this that wouldn't destroy the signal, which is what an FM modulator probably does...but if you're just listening to lossy .mp3's that probably wouldn't bother you.

Whats the make and model of your receiver?

I have a Dennon amp and know that they have one listed with an ethernet port..as for wirless you will be paying alot and will have limited signal strenght..hard wiring still better choice so far that I know