Am I right in thinking that the essentials license is a 6 Socket license with a VC license also?
Can I use it on a 4 socket Server and a 2 Socket server to make up the 6??
check this paper:http://www.vmware.com/files/pdf/vsphere_pricing.pdf
As per this paper, essential plus support 6 cpu licensing and you can use 4cpu and 2 cpu server.
Yes and Yes. The Essentials or any other license calculates the number of processors that are there in the server. if you apply it on a server with 6 processors it will calculate and use six licenses.
So the answer is yes you can use it as 4 and 2.
And yes it comes with 6 processors license and a vcenter license.
According to http://www.vmware.com/products/vsphere/compare.html, the Essentials kits support "3 servers with up to 2 processors each".
Btw. the documetation mentioned by john23 also says: "Both editions include vSphere processor licenses and vCenter Server for Essentials for an environment of up to three hosts (up to 2 CPUs each)"