If you're using the preview version of the recently announced Windows Phone Developer Tools and are champing at the bit to get the final Visual Studio 2010 bits, you might want to hold off for a few more weeks.
It turns out the final VS 2010 product is incompatible with the Windows Phone Developer Tools Community Technology Preview (CTP), as Microsoft officials acknowledged in a blog posting on April 12.
From the post from Charlie Kindel, Microsoft Partner Group Program Manager for the Windows Phone Application Platform & Developer Experience:
"If you install the retail (RTM) release of Visual Studio 2010 on the same machine on which you already have the Windows Phone Developer Tools CTP, you will be unable to build your Windows Phone projects. Further, while the Windows Phone project type will continue to appear in the File/New dialog, you will not be able to build Windows Phone 7 applications."
Kindel said Microsoft is planning to release an updated version of the Windows Phone Developer Tools "within a few weeks." (There's a sign-up page for those who want to be notified once that update is available.)
One way to get around the problem is for testers to continue to use the VS 2010 Release Candidate, instead of the final bits, until Microsoft releases the updated CTP. Kindel also suggested some workarounds for those who want to use the final version of VS 2010, including installing VS 2010 to a Virtual PC image or installing VS 2010 on another machine. He noted that installing the Windows Phone Developer Tools preview to a Virtual PC image is not supported.