Windows Live ID - Platform Neutral
I know there are probably some folks who roll their eyes when Microsoft uses the term "platform-neutral":
Windows Live ID Web Authentication 1.0 SDK
Brief Description
The Windows Liveā¢ ID Web Authentication 1.0 software development kit (SDK) gives you a platform-neutral way to bring the power of the Windows Live ID authentication service to your own Web site.
But in this case, there's some meat on them bones:
System Requirements
- Supported Operating Systems: Linux; Windows Vista; Windows XP
My guess is that in this case, you could translate that to...we're listening.
Download details: Windows Live ID Web Authentication 1.0 SDK