Formatting for projection?

I'm going to be having some shots included in a presentation, and I've never done this before. They're going to be projected in a medium size room on a screen. Is there any thing I should do to process the shots for this? Minimum size and/or ppi, or whatever? Or, just leave them as is?

Thanks.

I leave them as is and seem to work pretty well. Depends on the quality of the projector, too, at least in some part.

Don't have a lot of experience, but when I have done such things, I resize them to the resolution of the projector and sharpen to whatever I think is "appropriate" to avoid processing from the projector's software as much as possible.