If you haven’t already heard there is a new release of the Windows Phone 7 Developer Tools available which is compatible with the RTM release of Visual Studio. Before you install you need to uninstall the previous version and this is where you might have problems. See this tool for cleaning up your machine:-
Okay, now you’ve safely removed the old bits you can download the new installer from here:-
Read the release notes:-
In particular there is a breaking change if you open existing projects – the WMAppManifest.xml requires some extra items to describe the application’s capabilities. There is also an issue with including Authenticode signed dlls (this includes official Microsoft libraries), you can read more about it here:-
Check out an overview of what is new in this release:-
Finally to end on a quick tip – Assuming you install on a machine without Visual Studio 2010 the “Visual Studio 2010 Express for Windows Phone” displays a simpler user interface than its big brother. You can quickly enable extra goodness by going to Tools > Settings > Expert Settings. This enables more menu and toolbar options and is definitely worthwhile if you are already familiar with Visual Studio.