The address for the Woody Guthrie Archives and Foundation mentioned earlier in this thread is out of date; earlier this year they relocated.

The new address is:

125-131 Main Street
Suite #201
Mt. Kisco, NY 10549

Tel: (914) 241-3844
Fax: (914) 241-0299

Office hours are Monday-Thursday, 10:00AM-5:00PM Eastern Time.

Click here
for their website.