What would happen if I connect a bluray player to a projector who's resolution is less than 1080p?

I'm looking at projectors to buy and my budget will not be able to accommodate a high def. projector. I found on the market projectors rated at 1240 x 768 (not exactly, i think but just about right) and I'm wondering if i can view bluray movies on such projectors? Do bluray players, in general, allow u to select the output resolution? Will the picture be scaled down or cropped? All help is very welcome as I am new to this projector business and salesmen here are no help. Thanks

P.S. plan is to buy a projector now and then buy a bluray player in the summer.

your projector will "likely" accept a 1080i/p signal at various fps rates and convert it to the pj's native resolution