I found a great little app on Facebook that offers a free service for adding custom tabs to your Facebook Fanpage. It's called Woobox. The video below will explain how to get to it and use.
Check out two of my pages that I am using Woobox for tabs. http://facebook.com/HaveaBallShopping and http://facebook.com/laceycosmetics . Really easy to use, so try it out.