Microsoft just announced that jQuery will be supported in Visual Studio 2008 SP1 and shipped with ASP.NET MVC.  Scott Guthrie mentions that an add-on for Visual Studio 2008 SP1 will be made available in a “few weeks” to provide intellisense for jQuery and that ASP.NET MVC will use it for Ajax server-side helper methods.  The ASP.NET AJAX Toolkit will also be using jQuery for higher-level controls.  

If you haven’t played around with jQuery before it’s a very compact JavaScript library that makes performing style, selection and animation tasks a breeze.  You can accomplish a lot with very little code.  A nice PDF on getting started with jQuery that I’ve personally found quite useful can be found here.  Read more about support for jQuery in Microsoft products here, on Scott Guthrie’s blog here and on Scott Hanselman’s blog here.