Microsoft Commerce Server 2009 code name "R2" - October 2009 Community Technical Preview is the fourth pre-release build of next version of Commerce Server. Please note, this pre-release build isn’t feature complete, and includes several breaking changes that’ll impact your development environment. Please consult Commerce Server 2009 "R2" Readme and Quick Installation Guide for more information. Note: Given the pre-release nature of this release, not all functionality is currently available. The release is for evaluation purposes only and is not intended to be used in a production environment. The October CTP will stop functioning on June 6, 2010.
More info: Download