You might like to take a look at this dulcimer website - the lady who runs it can be contacted by email if you click on the "Email Webmaster" tab, just above where it says "NEWS!!" on the white background. (Leeneia - she also runs the big harp chat group at Yahoo, tho you may know this already.)

http://www.dulcimers.com/

There's also a nice general website for zither-y type instruments here, though they're unfretted:

http://www.fretlesszithers.com/
Click the link in the grey sidebar on the left which says "Sound Clips" if you'd like to hear any of them being played. After the new page loads, just scroll down it and click on the individual tune titles, and - if you have a player installed - you should be able to listen to them.