The Cylinder Preservation and Digitization Project makes available recordings pulled from about 6,000 cylinder recordings from the good old days. The collection -- which includes ragtime hits, presidential speeches and more -- is searchable, and you can download MP3s, stream the files or whatever.
Search the collection for "accordion" and you'll turn up some great stuff, like this 1908 recording of the "American Polka." Listen to him go!
Beyond squeezeboxes and polkas, you can listen to Teddy Roosevelt wax eloquent about the right of the people to rule or just generally lose yourself in a historic wash of sounds from yesteryear.
This is really a goldmine loaded with musical treasures.