The Swedish Public Radio has two channels devoted to christmas music only. The channels are available between 26th of November and 9th of January. Both stations are available online:
P2 Klassisk jul, traditional christmas music
P4 Bjällerklang, popular christmas music
As a service to those of you that are technically or "swedishally" challenged, I've also added them to the sidebar of this page. Just press play.
The Norwegian public radio also has a channel fully devoted to christmas music.
Listen in online at NRK Julemusikk.