We gave Airtime a go over the weekend but we came across two showstoppers. One was that we couldn't add any media (MP3s or WAVs) via its web interface. This did work running the airtime-import command as root but thats not a workable solution. The other major issue, which I think Len already mentioned was that Airtime doesn't seem to have any support for live feeds ie Skype or a mic input. It would've been nice to control the station almost entirely from a web interface but it looks like we'll have to try Rivendell instead now.