Here's a good site to help you choose what type of
projector is best for you. I had one in my middle
school art classroom. The lamp went out after 2
years and the principal got a new one (about $300).
My suggestion is that you try to get an XGA projector
for better resolution. They are expensive, but getting
more reasonable every day. Also, to make the lamp last
as long as possible let it cool down before shutting the
projector down. I used to run continuous slide shows for
hours as parents came into the gym for parent/teacher
conferences. It really sells your program.