Which video cards will fit in my Dell Latitude D600?

I have a D600 with a Radeon 9000 video card and would like to upgrade. But laptop cards seem to come in several different configurations (i.e. physical dimensions) and I do not wish to disassemble my latitude to find out just yet. Can someone tell me which ones work with my laptop, and especially are the cards which will work in an Inspiron cross compatible?|||Laptop graphics upgrades are not normally possible as they are built in graphics, normally time to bite the bullet if needed. D610 is not that much of an upgrade but you may get a bargain as they are end of life, but the new D620 is a cracking machine.