It should "just work" if you have SL or Lion, and a recent ZCS. You start typing the location name into the location field in the meeting in iCal, and it autocompletes. When you save the meeting, an invite is sent to the location.
Except...you might have a look at
Bug 66406 – [iCal 5.0.1] autocomplete not working in iCal 5. There's a bug in Lion that affects autocompletion, but there's a workaround.