In reply to GridNorth:
Sicily Rock (author Scott Titt by the way see his post) is the better guide if only going to San Vito. There is another guide that covers the whole of Sicily (Roccia del Sole, has an English version), including San Vito, but only has topos, whereas the Sicily Rock guide has good photos. Huge amount of climbing elsewhere in Sicily covered in the Roccia del Sole guide. Neither are cheap