Space matching (at least as I use the term) is basically just space switching AND automatically compensating for the jump in animation that happens when you switch from space to space. This is one way to set up space matching for the space switching setup I showed in an earlier video. Word of warning . . . most of this video is python scripting and most of that is just getting the info we need into and out of the UI. So if you're not into that kind of thing . . . you've been warned :)
For those interested in more in-depth python UI stuff, definitely check out Jeremy Ernst's (try saying the plural or possesive of "Ernst". It's hard!:) videos: vimeo.com/jernst
P.S. Apologies for the squeaky chair!
Space switching is essentially creating "virtual" parents in order to control the movement of an object or control. With only a tiny bit of setup this allows you to change what drives the behavior of different parts of your rig at different times. This video goes over some of the concepts of space switching, what it is, how you might use it, how to set it up, etc.