Free pdf scores to the choruses of Handel's Messiah made from the 1912 Shirmer score are available at this link.
http://singharmony.com/samples/messiah_scores.php
We also have excellent part-predominant teaching CDs for each part and a licensing program that makes it affordable to equip every member of a choir with his/her own CD.
Jim Taylor, President
Singharmony.com Inc.