I put latitude and longitude on a bunch of my images on the commons. It'd be nice if there was a standard for that, and we could probably tag a large portion of the images there.
How do you do that out of interest? GPS? Can you give an example URL.
Lots of UK place articles have UK grid refs and so on which could be extracted, although they need conversion. I would add more geo data if there were standard templates etc. I do have a GPS card somewhere, but I wish my camera had it built in.
I am very keen on adding geolocation data to wikipedia. The google maps interface is nasty though - more interested in building it into WP itself.