How many pictures can a 2gigabyte memory card hold?

It actually depends on a lot of different factors, but the short answer is that the range is going to be between say 80 pictures (powershot G10 in Raw+JPEG mode at 14.7 MP) and 16,000 pictures (Any digital camera at it's lowest resolution, and highest compression);and no I'm not joking. It really depends on your camera and your settings.