This is the most amazing thing ever and I am so excited about it.
Google is mapping museums the same way they've mapped all the streets. You can walk through and see works of art in great detail. They've not mapped the entire National Gallery in London yet, so they've not made it to my favorite piece which is Meindert Hobbema's Avenue at Middelharnis, but I'm sure they'll get there eventually. This would have been a great tool to have when I took Art History. It was often hard to find works of art, and when you did, they were often a little black and white picture in a book. Check it out.