I'll second the Fiddler's Fake Book as a good place to start. In fact, my husband and I need a second copy even though neither of us plays fiddle...he plays mando and I do keyless flute and mountain dulcimer and reading off the same copy gets tricky since our bi-focals aren't compatable.

Another good source of tunes are the three volumes of The Waltz Book. Waltz's are generally played slower than jigs and reels and many of the tunes are lovely and very accessible for the beginner.

Above all, have fun and find other folks to play with.

Enjoy!