I got contacted by SearchServerVirtualization.com to write an article about OpenVZ, and like... it was actually a paying gig. :) In the article I introduce OpenVZ as well as explain the process container form of virtualization. Obligatory quote:
There are a number of virtualization products for Linux and while I have used a number of them, the one that best fits my needs is OpenVZ. OpenVZ uses a form of virtualization called "process containers." OpenVZ is not a hardware emulator nor a virtual machine but a form of operating system-level virtualization that offers a way of grouping processes (running programs or system services) together to create a Virtual Environment (VE) or a Virtual Private Server (VPS).