TechwareLabs has published an article about Network Security and a Setup Guide. Here's a clip from the article:
Just a few years ago I was clueless about why I should secure my wireless network. I didn't care if other people used my wireless signal to surf the internet, and I thought it was too much hassle to figure out how to encrypt my network. It took me getting my credit card number stolen and my credit rating destroyed before I finally decided to take network security and the security of my data seriously.