This article will give you a brief overview of installing Snort on a Debian system. After reading this, you should have a basic setup logging daily to a local mailbox on your home linux system.
Read it here
If you've had a look at the Snort site, you will notice that the latest sources available are significantly newer than the packages available through Debian. In Part II of this series, I will go through the installation of the latest release available from the Snort site.
Before reading this, you should have an understanding of what a NIDS is used for and how it works. It would also be beneficial to have a good understanding of the TCP/IP suite, although this article will only cover basic installation without analysis of Snort's output.