Eagle's Whistle (celtic trad) http://www.kazu.org/sun.html
Webcasts live on Sunday 8-10pm (GMT) don't know the USA time but the website has schedules etc.
UK Bradford Community Radio has a show by Tim Moon on Monday's from 8pm to 10pm (repeated after midnight)and I've caught it going on longer than scheduled anyway. It is webcast on www.bcb.yorks.com