If you want to include the source? It's a little more complicated. You'd need both the Chipmunk src/ and include/ directories as well as the Objective-Chipmunk/ directory from Chipmunk Pro (I'd assume you want the fast vectorized solver too in HastySpace/).
Really, I'd just recommend grabbing the ChipmunkPro-iPhone/ directory built by the iphonestatic.command script. That has everything you need. Once it's linked, the size of the lib is not very big. I haven't actually checked in a while, but I think it's like 100-200 KB.