Note: This article is outdated now. I published a new one for the latest versions of Snort (22.214.171.124) and Ubuntu (16.04). You can also probably visit sublimerobots.com for the most up-to-date information on this process.
I've been playing with Snort a lot lately. I installed it on my home network using a switch that does port mirroring. I also created a Snort virtual machine that I can use with a laptop and a network tap to diagnose other people's problems. I picked up a SharkTap Gigabit Network Tap for that. It's really just a hub though, and I had to make sure I wasn't sending any traffic back into a tapped network with it.
First I'll explain how I installed Snort at home.
Snort on Ubuntu
I used a guide on Snort's website for installation on Ubuntu 14.04 LTS. I had some issues with it, which I will describe below. Note: The author's website makes some of these corrections and may have the most recent information.