Found this on Ebay,looks interesting as well as cheap enough,but does it work?I believe the projected screen resolution is 320x240,so I can't imagine its very sharp or bright,claims to have up to a 40" screen size.
Mini Projector for iPhone 4 and 3GS (SD, AV IN) on eBay.ca (item 260767789284 end time 18-Apr-11 18:28:16 EDT)
Mini Projector for iPhone 4 and 3GS (SD, AV IN) on eBay.ca (item 260767789284 end time 18-Apr-11 18:28:16 EDT)