Kudos to Microsoft for releasing their Google Maps competitor: MSN Virtual Earth.
It's not quite as complete as Google Maps yet but give 'em time. MS have been in this space for a long time (have you heard of TerraServer?) and they'll no doubt improve quickly. And they're actually ahead in some areas - much of their data is very impressive, in some cases providing closer satellite shots that Google Maps.
Oh, and it would be an oversight not to mention that Virtual Earth also has a set of developer API's. Incidentally, that website was created none other than our own Dr Neil.
Speaking of Google Maps, they recently made a nice tweak: there is a new 'hybrid' view that overlays the road and satellite images. Both Virtual Earth and Google Earth had similar features.
Competition is good! Now if either of those products only had good Australian data...