Microsoft has a downloadable preview of Acrylic (the pixel- and vector-based drawing package that is part of the new UI development suite known as Expression) on their web site:

Microsoft Expression

These tools were shown at the PDC, they’re pretty slick, and they integrate into Visual Studio 2005 perfectly making them an obvious choice for shops that develop the next generation of Vista and Avalon applications.

While I’m personally waiting for Sparkle (the actual XAML UI design tool), this is a good introduction into how the tools will function and might be a nice jump start.