I'm here at Microsoft listening to Jef talk about LINQ internals at the Dallas C# SIG meeting. Since I love to multitask, I wanted to take the opportunity to post this link to free eBooks for LINQ, ASP.NET AJAX, and Silverlight. I've only started reading the LINQ book, but really like it so far.
Fair warning: you need to have an MCP number to register and download these eBooks. But of course, if you want to become a Microsoft Certified Professional, contact Improving for training and "second chance" exam retake coupons.