How to test multi touch in the Windows Phone Emulator
This Multi-Touch Vista project on codeplex provides a Windows service which emulates a touch screen, with multiple touch points. You can use this service to test multi-touch apps even if you don't have a device.
To install this service, follow the steps from the download page.
After installation, services.msc should report the Multitouch driver under services:
Start the service and set the configuration.
Note that it can take some time to get used to get used to the multi-touch emulation.