There are solutions to do this in a really bad way (like Matrox's dual- or triple-Head2Go), but those only work with VGA and they make your computer think all the extra monitors are only one monitor -- which is bad for a number of reasons.
There was one post by a guy who had another piece of equipment that allowed him to run 3 external monitors on his MBP as *real* separate DVI monitors, but I don't remember the name of it. I got the impression it was really, really expensive though.
Try searching, this has been talked about a LOT.