Modern Songs for Guitar and Dulcimer
Dulcimer Resources:TABS/Books/websites/DVDs
The whippersnappers in the local ukulele club taught me a couple of Death Cab songs that I think would sound wonderful on MD and guitar: I'll Follow You Into the Dark and Stay Young, Go Dancing.
In return, I teach them Bob Dylan songs. You Ain't Going Nowhere. Wagon Wheel (not entirely Dylan, but hey). Mr. Tambourine Man.
What about those '70s folk groups like Steeleye Span and Fairport Convention? All those versions of Matty Groves and John Barleycorn aren't "modern songs" but they do seem to split the difference between indie rock and 17th century ;-) Also Paul Simon in his Scarborough Fair and April Come She Will period.
Are you playing chords, playing melody, or both? The chords for all these songs are easy to find on the internet. Sheet music for the melody can be purchased in a fake book (be sure it includes the melody lines and not just chords). Dulcimer tab will be hard to find. If you need tab, then Matty Groves and john Barleycorn are looking better than ever!