The announcement is summarized as follows :
"CICS Transaction Server for z/OS (CICS TS) V5.1 open beta introduces cloud-style CICS development, deployment, and operations, by delivering:Date of availability is June 13, 2012. From that day onwards you will be able to download CICS TS 5.1 by visiting : http://www.ibm.com/cics/openbeta.
The combination of these two sets of capability areas will greatly simplify the assembly, deployment, and lifecycle management of CICS applications, delivering many of the characteristics found in private-cloud computing systems. CICS TS V5.1 open beta gives you the opportunity to explore the concept of a cloud-style CICS deployment in your own environment."
If you want to have more information on this announcement and some related announcements on CICS Explorer, CICS Configuration Manager plug-in, CICS Performance Analyzer plug-in, WebSphere eXtended Transaction Runtime and IBM Rational Development and Test Environment for System z, then do take a look over here at the Cics Portfolio eNewsletter. It really provides you with lots of additional information.
Oh, by the way, a tweet from IBM_CICS brought me to this page where you can find all Announcement Letters for CICS Products' brought together.