Went nosing about the web for something to help me generate random continent outlines, and see what I found:
It can randomly generate a world based upon simulating a number of tectonic plates moving about.
This decides where mountains are, and it also tries to roughly assign land climate / vegetation based upon distance from the equator.
http://www.reddit.com/r/worldbuilding/c ... generates/
Download link: (.jar file runs under Java runtime 6 or higher)
http://dl.dropbox.com/u/7700226/ContinentGenv1.jar
Figure I can export off a random world and import the image into Hexographer or something to do some more work on it.