Mohit Gogia blogs in detail about Device Emulator Manager's Automation Interfaces
Visual Studio 2008 Beta2, as you know ships with Device Emulator V3.
I have already blogged about the wonderful features that Device Emulator V3 enables, including a programmable automation interface to the Device Emulator Manager, the ability to "clone" emulator instances from the manager's context menu, and the ability to configure you own emulators using simple XML.
My colleague Mohit Gogia, a developer on the Device Emulator team, blogs in detail about IDeviceEmulatorManager: the Device Emulator's automation interface.