http://blogs.msdn.com/b/ericlippert/archive/2009/11/12/closing-over-the-loop-variable-considered-harmful.aspx

http://msdn.microsoft.com/en-us/library/ms229043.aspx

  http://dixond.blogspot.com/2010/08/everything-what-you-might-want-to-know.html

Good post   http://blogs.msdn.com/b/codeanalysis/archive/2006/04/27/585476.aspx