Once I had got my iTunes library downgraded to 10.7 and liberated some of my DRM'd media I thought it would be awesome to use my Raspberry Pi as an Airplay Receiver...
Head over to http://www.raspbmc.com/download/ and follow the instructions to download and install Raspbmc. Once you've prepped your SD card, popped it in your Pi hole and got it booted it should start the installation… at this point you can grab a coffee
In older versions of Raspbmc you had to SSH in and enable the web server
in /home/pi/.xbmc/userdata/guisettings.xml
In the latest version this was already enabled, so I just picked up my phone, downloaded the official XBMC remote app from the Android marketplace (or iTunes store if you are that way inclined).
A couple of points of note when adding your host in the XBMC remote app.
If you don't know your IP address and your Pi is not automatically found
you can find this from your local router. The HTTP port is 80 by default
in Raspbmc (not 8080) and the password is blank, although I configured
username xbmc and password xbmc and this works just fine!
Once set up it was easy to select my language, enable airplay and start streaming!