Available as a free project via Microsoft CodePlex site, the Windows Phone Power Tools are designed to extend the Windows Phone SDK and simplify the work that devs have to do.
"The Windows Phone Power Tools are a natural extension to the developer tools that come with the Windows Phone SDK," read the description of the CodePlex page.
"Instead of allowing you to only install developer xaps the Power Tools let you test update scenarios by allowing you to update an existing developer app."
"Instead of having to step through the IsolatedStorage file browser on the command line, the Power Tools provide a GUI to allow you to interact with your applications."
You can download Windows Phone Power Tools from the CodePlex site.