I installed Virtual Box via aptitude, the way you normally do if you're on the Ubuntu GUI. From there, creating the VM is a matter of typing a few commands in order to generate the VM name, NIC, hard drive and size, assigning RAM, etc. Once the VM has been created, you connect to those via remote desktop protocol. I can even connect to one of those via Internet because I assigned a public IP and open a few ports on my home's firewall.
It is like running VMware on a headless server; some commands are even the same. I think I have a link with instructions and a small Word document I created for each command. PM me with your email address, I will send you the info.
I like it that way because uses very little resources. I run Virtual Box on my Ubuntu laptop via GUI (a different Virtual Box setup) but if you want to save resources or use a Headless server, is the way to go.