I have donated 2 cars over the years to the American Lung Associaiton.
I highly recommend this organization. You must first sign over the title and mail it to them, they will send you a copy back. When they receive the title they will contact a local towing company to tow the vehicle at their expense. Their web site has all the forms to fill out, even the tax form. http://www.donateyourcar.com/
I recently donated my 1988 Honda Accord with 182K miles and replaced it with a 2001 Acura TL with 69K miles.