Wal-Mart sells a speaker mount that works great as a projector ceiling mount. the link here takes you to their web site and shows a 5 pack of the mounts. a 2 pack is available in the stores for $7.98

http://www.walmart.com/catalog/product.gsp?product_id=2684088

 

Email me for questions on how to use these mounts. No drilling on your projector is required. the small grey plate unscrews, and you screw that shaft into the hole on the bottom of the projector.