I had heard a while ago that most people don't dream in color. I was telling someone this, and I was not believed. So, I did some poking around on the Information Superhighway (always a dangerous prospect). It should have come as no surprise that there is contradictory information. However, I think the general consensus is that most people dream in color, but it's forgotten if the color is not an important aspect of the dream, if it is not noted right upon waking. I also saw something that suggested that people who pay more attention to color in waking life will remember color more in dream life, and that you can train yourself to remember colors in dreams by focusing on them.
It might be interesting to see some actual studies. Of course, actual studies written by actual scientists might well be unreadable.