You might be thinking of Liquid Motion. Some say they bought it to kill it (it was Java based). MS wouldn't do that would they?
[link|http://www.microsoft.com/office/previous/liquidmotion/default.asp|http://www.microsoft...otion/default.asp]
[link|http://cws.internet.com/reviews/webimage-msliquid.html|http://cws.internet....age-msliquid.html]
This XAML thing looks to be an all in one XML+XUL+HTML+CSS+PDF+SWF thing that compiles to .NET binary. They plan on getting everyone to use it for UIs (Longhorn's UI will probably use it), "portable" documents and the like. This "Sparkle" is likely a Flash Studio like authoring tool. Some future Visual Studio will probably have a more programmer oriented UI design tool as well.