I will be visiting Frankfurt and Heidelberg in a couple of weeks. I wanted to know of a good place to find a German Wooden Music Box, the kinds that have little moveable people and maybe a black forest one?

In Heidelberg go to Kathe Wolfharte (I'm sure I just annihilated the spelling of her name) but you can't miss the shop. It's got all sorts of great knick knacks (though mostly Christmas).

I can attest that Kathe Wohlfardt has good stuff at fair prices with good service. We have purchased from her many times and had things shipped home. They always arrived in good shape and on time. She has a web site that you can find on the internet.

I agree that Kathe W. has great a German selection. I went to look at the cuckcoo clocks. They were gorgeous but beyond my price range. Although Bob said the prices were reasonable, and probably so for the great quality, I found everything too pricey for my current budget. You can find her on the web to give you an idea of prices.
Beautiful stuff, though

http://www.wohlfahrt.com/

Heidelberg: Besides Kaethe Wohlfahrt which is on the corner of Universitaetsplatz in Hauptstrasse,
there's another shop with wooden toys and handcraft articles on Hauptstrasse. Further up towards the castle and church on your left-hand side.
(When I was a child they had a real little gold fish pond in the window - really impressed me...)