As mentioned by others already, the slicehost articles are great for installing and setting up a server (they have detailed guides for Ubuntu, centos, debian, etc.)
A few things to be aware of:<p>1. Security. I can't stress this enough, as people new to managing their own VPS can end up doing some bad mistakes with respect to security, e.g. leaving root account login enabled, weak firewall etc. Make sure you do a bit of googling to make sure you get a good hang of the security aspects of hosting your sites on your own VPS.<p>2. Although you mentioned that your sites are low traffic ones, you might still want to choose a light weight webserver like nginx/lighthttpd over Apache, which can be quite heavy weight and need a larger slice.<p>3. You won't have any mail server by default, which is a free benefit in a shared hosting environment. Setting up and managing your own mail server can be nightmarish.. Look into something like Amazon Simple Email service for that.