For as much pain as it caused a while back with "The Plug-In That Shall Not Be Named" it looks like we can really bring in Google Earth imagery into NASA World Wind, as long as we follow the rules. Confused yet? It seems many people are and Adena Schutzberg at All Points Blog tried to wrap their brain around it.
Read that post for the full details and head scratching, I will just point out the major points.
"The terms of the license that we signed include a promise by us to prevent anyone from accessing the data other than through Google software." And, that, while it sounds restrictive is amazingly open, especially when it comes to Google Maps, which has an open API, which is "Google software."
There are two main mapping programs that use this that I can think off right now: Flash Earth and OpenLayers, they both show imagery from Google and they can do it legally.
With quite a bit of patience Frank explained that OpenLayer is doing everything correctly. It has an API key for each of the API providers (if needed) and follows all the rules of the license. So, how is this different from the Gaia team noted above that got shut down? That group was accessing the data directly from Google servers and not, as stipulated in the license, via Google software. (Google Earth has no API like Google Maps does.) Frank even showed me the code where OpenLayers dutifully uses its API key to pull in tiles from Google Maps. Google, he noted, even contacted the MetaCarta team to ask if there was any thing needed to further their implementation!
So, going by the logic and thoughts of the above. The World Wind community can get a Google Maps API and re-create the "The Plug-In That Shall Not Be Named" into the Google Maps Layer Plug-in and users can once again view Google Earth imagery within World Wind. And it will be legal because we will follow all the rules for it's use.

[...] under World wind , worldwind , EULA , google maps , imagery , Google Earth , google Reading Chad’s blog, it seems that a Google map plug-in for World Wind is legal, some other recent blog posts are also [...]
You mentioned two pieces of software that use the Google Maps data: OpenLayers and FlashEarth.
I see no indication from Google that FlashEarth is not violating the terms of use. Although I see that the API javascript is loaded into the browser, I'm not convinced that that's actually enough, and it would depend entirely on how FE is using Google's API to get the data out.
The OpenLayers use case is not something that seems like it could be applied to WorldWind. OpenLayers instantiates a GMap2 object on a div element inside a browser, which is why it is on the 'right side of the law'. In general, Google's terms of use mean that you need to use the API only to put the tiles inside an HTML element on the page. OpenLayers does that. I don't think WorldWind can.
The best thing to do is probably just to email Google and tell them what you plan to do, and see what they say. It sounds like you have some kind of idea on how you're going to implement this while staying on the 'right side of the law', but I can't envision it. The words of John, and Adena, are not gospel, and your interpretation of what is said does not necessarily put you any better off than you were before.
If you want to talk more about it 'live', you can find me on #planetgeospatial on irc.freenode.net. You can join via the web via CGI::IRC for planetgs.
Oh, we already know what Google will say if we ask... they greatly dislike the idea
Webmapping API Licenses and Data Access...
All Points Blog offers an clear and to-the-point entry on the relationship between data and API licenses for webmapping apps, specifically Google, Microsoft, Yahoo! data into other webmapping apps such as OpenLayers. Meanwhile, The Earth is Square wond...
We could show the tiles in the internal browser tied to the current viewing location, maybe even using openlayers.