Using the device debugger with a zune connection is a great advantage of Windows Phone 7 development. But if you want to test some choosers ( for example the PhotoChooserTask) you can not do this with a running zune connection.
Fortunately there's a tool that solves the problem by removing the need to have the Zune software running while debugging. It's called the Windows Phone Connect Tool. It was released as part of the recent update to the Windows Phone Developer Tools. This tool allows you to close the Zune software, after your phone device is connected. After this it is possible to debug choosers such as the PhotoChooserTask.
Here you can get a batch file to do the work for you: