http://msdn.microsoft.com/en-us/library/hh242985(v=VS.103).aspx
http://msdn.microsoft.com/en-us/data/gg577611
http://msdn.microsoft.com/en-us/data/gg577609
http://channel9.msdn.com/tags/Reactive+Extensions/
http://blogs.msdn.com/b/rxteam/
http://www.codeproject.com/Articles/162731/Reactive-Face-Using-Reactive-Extensions-Rx
and more by google(ing) it yourself.