Web and iPhone maps provider CloudMade can add a few more platforms to that list. Today it acquired German geospatial company One Step Ahead to incorporate Android, MeeGo and other mobile platforms to its suite of developer tools. CloudMade will also incorporate One Step Ahead's offline/online map technology, which passes a few map updates at a time.
The non-profit built for "opening America's government" has created an app to show off its Congressional data, as well as its API (our Sunlight Labs API profile). You can't get this app on the web, though, as it's available exclusively for the Android phone platform.