Wow. This is an interesting development. Visual Studio is going to ship jQuery in a service pack and in future versions of Visual Studio. There will be intellisense support, PSS support, and Microsoft will be submitting patches back to the jQuery library.
One other interesting question: How will companies who are normally allergic to OSS code react to this if their developers start using jQuery when writing their applications?
In any case, this is a big step forward for Microsoft and OSS in general. Hopefully we'll start to see Microsoft shipping more and more OSS software with their developer tools and maybe Windows someday.