if you have a laptop, you could use nikon camera control pro 2 to act as an intervalometer. http://imaging.nikon.com/products/imaging/lineup/software/control_pro2/index.htm
there is an intervalometer within the program
its a very handy application, lets you control all aspects of the camera from the computer!
*edit* i just realized the d200 has a built in intervalometer....just did a quick search and there is a how to for the d200 and the built in intervalometer on ken rockwells site here http://www.kenrockwell.com/nikon/d200/users-guide/menus-shooting.htm
about 3/4 of the way down the page