Hi, Merrilee (nice name) - click here to get to www.ascap.com, and here for www.bmi.com - ASCAP licenses more music, but BMI is the one more likely to handle folk and pseudo-folk stuff. Both pages have links to databases that list the songs they license. Note that although somebody may claim a copyright on a song, it may still be a traditional song and their claims to rights for the song may be based only on their arrangement.
-Joe Offer-