I have posted up the unsupported code to allow support for printing a Virtual Earth Map in IE6, IE7 and Firefox:
http://www.viawindowslive.com/Articles/VirtualEarth/PrintinginVirtualEarth.aspx
There are two versions of the code, a compiled ready to use version and a full source code version. Importantly if you don’t need to support tile layers then it is a simple javascript file you need to use in your project.
Do keep in mind this isn’t supported but for those people who need to provide printing functionality today this will help you significantly.
John.