O'Reilly Radar > Where 2.0: Google Maps API
Another link clear out. The API looked interesting, but lacking hooks into routing is a big thing. At about the same time Yahoo released their mapping API. Yet another pissing contest in the brewing. I have yet to look at Yahoo's API, but it does not sound as robust from what I have read.
There is one thing I would like to see - the ability to get a route and send in a number of miles and have the number of miles follow along the route as say a highlighter. That way you could do something silly like track your running in reference to say a trip across the United States.