Today's Apress $10 deal of the day is Introducing .NET 4.0: with Visual Studio 2010
Deal is at http://www.apress.com/info/dailydeal
Details of the book are at http://www.apress.com/book/view/143022455X
I have been using Framework 4.0 for a year now and I am still finding out new things introduced with 4.0 - a book like this is a very welcome addition to my library.