If you are building Virtual Earth solutions with the JavaScript control, then you absolutely have to download this toolkit.  Chris Pietschmann just announced the first official release.  Here’s how he describes the toolkit:

“The Virtual Earth Toolkit is a set of JavaScript-based Controls/Tools that Extend Virtual Earth with functionality that is commonly implemented, but hasn't been implemented within the Virtual Earth JavaScript Map Control.
The Controls/Tools in the VEToolkit library are completely self contained, and don't require the use of any other JavaScript library to use other than Virtual Earth 6.2 (current version). This allows you to use this toolkit along-side any other JavaScript library (jQuery, ASP.NET AJAX, etc.); plus you can make use of it with any server-side framework of you choice (ASP.NET, ASP.NET MVC, PHP, etc.).”

Details are at:

http://pietschsoft.com/post/2009/01/VEToolkit-Virtual-Earth-Toolkit-v620125091053-Released.aspx