As announced at VMWorld 2012 in San Francisco vSphere 5.1 is now available. Also available are the products vCloud Director 5.1 and vCenter Site Recovery Manager 5.1.
Links:
Download VMWare vSphere 5.1
Documentation for VMWare vSphere 5.1
As also announced at VMWorld the one year old vRAM licensing model is now finally history – VMWare returned to the per-socket-licensing model.
By the way – this licensing model applies to vSphere 5.1 and vSphere 5.0, too! (as you can read at VMWare vSphere 5 Licensing, Pricing and Packaging document page 8)