As a complement to the already available Windows Phone 7 developer tools, templates for VB are now available.
Here is the full announcement from the VB team and a walk through of how to use it: http://blogs.msdn.com/b/vbteam/archive/2010/09/23/announcing-microsoft-visual-basic-ctp-for-windows-phone-developer-tools.aspx
You need to have the release tools installed and then this is a very small download and installs very quickly.
You will get the same “Silverlight for Windows Phone” under the VB templates and be able to easily bring up a VB based phone application. No XNA at this time.