Basic Airplay script
This is a pretty basic use of the new Airplay stuff. Select and set your Airplay devices:
tell application "iTunes"
set apNames to (get name of AirPlay devices)
set apDevices to (get AirPlay devices)
set rez to choose from list apNames with prompt "Select Airplay:" with multiple selections allowed
if rez is false then return
set apPlays to {}
repeat with i from 1 to length of apNames
if item i of apNames is in rez then set end of apPlays to item i of apDevices
end repeat
set current AirPlay devices to apPlays
end tell