Dear Chiffers,
I was messing around exploring the Sirius Satellite Radio site and saw that they have an address for Record Labels and Recording Artists to send their recordings for consideration. They have a few world and folk music channels (no irish or celtic that I could see…yet) that might be a good possibility for getting your recordings some airtime. 
The following info is on their Contact page at http://www.sirius.com/servlet/ContentServer?pagename=Sirius/CachedPage&c=Page&cid=1019257316790
Record labels and music artists:
Do you have a recording that you would like played on SIRIUS?
Please submit your recording to:
Attn: Music Programming Department
SIRIUS
1221 Avenue of the Americas
New York, NY 10020
Btw, they have a free 3 day offer for listening to Sirius on your computer available now - http://www.sirius.com/servlet/ContentServer?pagename=Sirius/CachedPage&c=FlexContent&cid=1083868829035&source=gaw&cp=010&occ=ACR0101000)
Sirius is an expensive service but apparently a lot of folks are listening.
Wishing you all a very safe and happy Fourth of July weekend!
Peace,
Fran
