The release over can be found on this page.
The page is mostly sales jargon, but does contain one interesting tidbit that ESX will not be supported after this release!
"For planning purposes, it is important to know that vSphere 4.1 is the last vSphere release to support both ESX and ESXi hypervisor architectures; all future releases of vSphere will only support the ESXi architecture"
Also, some exciting news for Essentials Plus users:
"VMware vMotion™ is now included in the Essentials Plus and Essentials for Retail & Branch Offices kits, as well as in vSphere Standard edition."