Thanks to user,delakota555, who replied to a recent Airplay post. I went ahead and looked into Shairport. Shairport is an open source AirTunes emulator. It runs in Linux and I installed it on my hacked $15 ArchLinux PogoPlug.
OK, this is pretty awesome. I had a spare $3 USB sound card dongle lying around and in less than 15 minutes, I had an Airplay remote speaker set-up using a PogoPlug V4 I had lying around. Why is this awesome? $20 in parts and you have yourself a streaming Airplay iTunes receiver. You can buy a few of these and litter them around your house for remote speaker set-ups.
Pictured below is the V4 PogoPlug, a USB stick, the USB sound card, ethernet and voila, Airplay!
The Pogoplug instantly shows right up on my iPhone.
On iTunes, I can stream music to multiple speakers around the house. I think I'll be investing in some more $15 PogoPlugs shortly.
As you can see below, I can stream Airplay music to multiple Airplay devices including the PogoPlug. I love this. I love the ability to walk from room to room, floor to floor and hear the same music streamed throughout the entire house.
I followed this blog post for a pre-compiled binary and that was it.