There's been some confusion around moving from V1 to V2 beta of Virtual Earth. Hopefully, this helps clarify the situation.
1. The first VE control was posted to http://www.virtualearth.com/standard/v1/MapControl.js.
2. It was then moved to http://dev.virtualearth.com/standard/v1/MapControl.js. (Same control, different location).
3. Now, the newest version is available @ http://dev.virtualearth.net/standard/v2/MapControl.js. This is what your applications should be using today.