Google Earth. Latest from Google.
Downloaded this software a couple of days ago, decided to try it out yesterday, it's amazing!! Check it out, Penang's actually featured, not like in the Yahoo maps thingy online. Of course, this is a software, so it'll be on the computer the whole time.. but it uses streaming to get the maps in.
Check it out guys... This is the free version, they'll be updating the details in the maps, i read somewhere you'd soon be able to zoom in on your own backyard... Not all over the world so soon yet though.