There are some over at
Shoutcast, just enter Christmas into the search field.
If clicking on the yellow "tune in!" button doesn't automatically add the station to your iTunes library, here's what to do: ctrl-click on the button, copy address to clipboard. Go over to iTunes, pick Advanced->Open Stream and paste in the URL.
(Just some explanation: the radio directory in iTunes is really just a list of shoutcast-type stations, you can use any MP3 stream.)