If you are using Visual Studio 2008 Beta 2, and are building applications for Silverlight using Javascript, there is a cool project from Justin-Josef Angel, which I recommend checking out.  Using Justin's library and Visual Studio 2008 Beta 2, one can get much richer Javascript intellisense experience for Silverlight.  Below is an example of the additional intellisense information Justin's library provides:

VS 2008 javascript intellisense for Silverlight w/o Justin's Library

VS 2008 javascript intellisense for Silverlight with Justin's Library:

For more details about his project and how to use it, check out Justin's blog.

--Omar Khan
Group Program Manager
Visual Studio Web Tools