I stumbled across ZoomIn today which is a New Zealand map site with lots of interesting features.
You can search with street addresses and get maps of pretty much all of New Zealand and explore via a Google Maps like interface. Included are optional aerial photographs of many of the regions. I like the way it uses Ajax to narrow down a search for an address as you type.
ZoomIn also provides the ability for users to comment on places, upload photo's and annotate in other interesting ways. A nice idea!
For developers they have a REST style API that allows searching for addresses programatically and retrieving the lattitude and longitude of the address found. Other API's seem to allow integrating map data into your own web apps.