Expression Blend 4 Service Pack 1 (SP1) includes support for building Windows Phone 7 apps and improved integration with Adobe design tools through support for the FXG file format, as well as bug fixes and stability enhancements.
Windows Phone support
When you install the Windows Phone Development Tools, you can use the design tools in Expression Blend to create Windows Phone applications, including Windows Phone project and item templates, graphics and animation tools, behaviors, and sample data. Once you’ve created your Windows Phone application, you can build it and then preview it either in the Windows Phone emulatoror in a Windows Phone device attached to your computer.
* Please note: If you want to design only Windows Phone applications, and you have already installed the Windows Phone Development Tools, you do not need to install this service pack.
Adobe FXG support
With the Expression Blend Add-in for Adobe FXG Import, available when you install Expression Blend 4 SP1, you can add Adobe FXG 2.0 symbols as UserControls in Expression Blend. You can also configure your FXG settings so that when FXG files are updated outside of Expression Blend, the files you have added to Expression Blend are also updated.