There is a Windows 7 netbook edition floating about cyberspace that is said to run on any netbook. It’s not the Windows 7 Starter Edition that ships on most of the netbooks over the last few months, but a customized version of Windows 7 Ultimate stripped of its drivers, language packs and other not so essential features.
This isn’t an official Microsoft build and seems to be taken from a pre-release version of Windows 7, so be aware that there is a good chance that the OS will expire if you don’t have a valid product key. The only way to ensure that you are actually getting Windows 7 is to just buy a legit copy yourself. The official Windows 7 should work well on most netbooks with 16GB or more.