On 03/15/2010, at Mix 2010, ScottGu announced the availability of Windows Phone Developer Tools CTP for free download. It can be downloaded from here
And more information about the download can be found here on the Windows Phone Developer Blog.
Also the developer home for Windows Phone is here
While installing the download package, I ran into an error that VC 10.0 was already installed. Turned out that I had Visual Studio 2010 Beta 1 installed on my machine, and the Windows Phone Developer CTP was not OK with that. Uninstalling the VS 2010 Beta 1 fixed the issue.
A bunch of other new technology that has been announced in Mix 2010 include
– Houston – A tool built in Silverlight that allows manipulation of SQL Azure. Again this is not something new but things are coming together nicely for developers working with Microsoft technologies.