Here is how to figure it out:
Go to wmware.com, then you look around and you'll notice the "Products" link where you'll check out one of the ones you mentioned. We'll start with VMWare Server and you click How To Get It. On that page it says:
(my emphasis)
End of my ultra short "how to browse the internet and find your answers"-guide.
I don't mean to sound condescending, but if you cannot figure out how to compare VMWare's products, are you then competent enough to manage a server and its VPS nodes running in VMs? Furthermore, why did you pick specifically VMWare if you have no idea of what their products offer? There are several others such as VirtualBox, Xen, or OpenVZ that can create virtual machines as well.