A new NASA Windows 7 theme is now being featured on the Windows 7 personalization gallery website. This site, for those that don't know, is a great resource for finding new ways to personalize your PC, including free themes, backgrounds and gadgets.
Recent additions to the themes gallery have included a handful of "Bing's Best" themes, including a very cool one – and one of my new favorites - featuring images from Japan (See: Bing’s Best: Japan here).
The new NASA theme ("Spacescapes") is an excellent follow-up to the earlier one showcasing imagery revealed by the infrared system of NASA's Spitzer Space Telescope. The Spacescapes theme offers gorgeous imagery of galaxies, dying stars and more. You can grab it here.