From this page you can download the EAP builds for ReSharper. If you are looking for the latest released version, visit ReSharper download page.
ReSharper 3.1 is released. ReSharper 4 EAP will start soon, but we started to publish nighly builds (simply raw builds from our continuous integration, will all weird things developers might check in before leaving the office at 11pm) for our very loyal early adopters
Read installation instructions to learn how to install ReSharper for Visual Studio Orcas