A auto electric place should be able to rebuild it or at least sell you some brushes.
Also might just buy a used pump motor either in the "parts for sale" section, or get a reman complete ABS System from
www.Priorreman.com . Thanks members get a discount.
edit...Did something cause it to burn up like a leaking Pressure Switch or bad Accumulator? If you don't fix that, you'll be looking for another pump soon. A local junkyard may have one either from a SC or I got mine from a Lincoln Towncar (It was a Taxi). Also there is a good article to MAKE SURE it is the pump and not a bad $15 relay here:
http://www.35ththunderbirdregistry.org/Tips/ABS.htm