It's been in the works for over a year now, and NASA, today, is finally releasing a SDK of WorldWind for Java.  Patrick Hogan, the Project Manager for NASA's WorldWind which, up until now, has been a Microsoft .NET application, explains in a JavaOne session yesterday: CNet Video.
The .NET application, version 1.4, is still available as well as the source code.  There's much speculation on the WorldWind open source community about the future of the .NET version.  Hogan says that NASA will turn it's efforts back to the .NET codebase as interest in the Java version picks up, but that hasn't stopped the community's worries.  On the Microsoft platform, ESRI has dominated the GIS space, while most of the innovation in open source GIS has been in the C++ and Java languages, geared to either cross-platform or linux use.  That's a bit of a generalization, but it's useful to see why a successful open source globe viewer like WorldWind .NET could easily (and quickly) be overshadowed by a proliferation of WW Java SDK based apps.

I'm hoping to pop out an Eclipse RCP based one, but that's dependent on how good the AWT/JOGL wrangling goes into SWT.

Here are my first impressions.

Meanwhile, another, usually under the radar, government agency gets all paranoid: (I've blinded myself with bad puns!) Intel chief: Curbs on public satellite photos may be needed, Vice Adm. Robert Murrett, NGIA director, May 8, 2007

05/11/2007 Edit:  NASA reupped their Sourceforge and their zip includes two demo jars (worldwind.jar 4.5mb, BasicDemo.jar 10k)which don't run.  For all those people looking to download a SDK and double-click stuff, they'll be disappointed.  Granted, it'd be nice if they did have working demos for simple people, but download it anyway and build it yourself, you'll be pleased.