I've been monitoring the nightly EAP builds of Resharper 4 and the latest ones have been pretty stable. While all of the features are not in yet (most notably full support for LINQ), there is enough in here to really get a sense for how it is evolving. I installed build 767 a few days ago and its working pretty well.

There is lambda support (meaning it works with them and has some refactors), extension methods, automatic properties, and more. It does support some aspects of LINQ such as intellisense, which was my biggest problem with using v 3.1 with VS 2008. So its definitely on its way. i know VS 2008 has refactoring tools built in but Resharper just blows it away in terms of the productivity boost I get.

Here are some links where you can check out the latest EAP builds or the EAP notes .