Of course, Carole, you do know that the absolute best folk songbook in the entire world is the Digital Tradition Folk Song Database, right here at the Mudcat Cafe.
If you prefer something printed on actual paper, I'd suggest a two-volume work called Jerry Silverman's Folk Song Encyclopedia, published by Hal Leonard, about $40 US. Smaller but more international is The International Book of Folk songs, by Norman Luboff and Win Stracke, about $15 US. both are readily available at the book merchants you'll find on our Help support the Mudcat page. I'll e-mail you the "Roamin" tune so you don't have to figure out MIDITXT or ABC your first time around.
-Joe Offer-