Just one more to add to the commonly used types of lamps that people want to use.

Can you use it? Sure, and people have. Is it a good idea? Probably not so much.

While CFLs are decent enough as lamps, consider the fact that places like Costco, Home Depot, etc use metal halide lights in their stores. Why? Because it's the cheapest way to get lots of nice white light. Flourescents work for lower ceilings where you need the light to be more distributed, but for a high ceiling where lots more light is needed, the MH lamps do the best job for the least energy cost.

A quick search shows CFLs to have an effacacy of about 60-72 lumens per watt. Metal Halide lamps are about 80-100 lumens per watt So even a best case CFL vs a worst-case MH lamp gives you a 10% increase in efficiency.

Then there's the sheer amount of power required. CFLs typically come in less than 20 watt packages, which is fine for replacing a standard household lightbulb, but not for producing the output of light required for an LCD projector.

One large problem with CFLs is that the area from which you need to capture light is relatively large. Most CFLs are over 2" in length, and nearly that in width. This presents a large problem in trying to gather the light into a projection lens as well. The reason why commercial projector lamps are so expensive is their small light emitting size. This further drives down the efficiency of using CFLs as a projection light source.

In the end, you can use about any lamp that emits light, but some are not very good ideas.