Aspen is a business oriented phone with the front QWERTY keyboard and candy bar form factor like Blackberry.  It has a 2.4-inch QVGA TFT touchscreen LCD, 3.2 megapixel camera, A-GPS with Google Maps, 3.5-mm audio jack, WiFi, and microSD expansion.

The most important thing is that it will come with Windows Mobile 6.5.3.  Although it sounds like a minor upgrade from version 6.5, it actually completes the UI improvement from Microsoft to a completely finger friendly interface.  The new version also support capacitive touch screen and multitouch support is enabled.  Microsoft has also improved browser performance with faster page load times and better memory management.

The original Sony Ericsson announcement is here.