if you're already using an extract, you're basically there. Just a few more supplies and one extra step. I made my tun out of a cooler I had in my basement, just had to buy some copper piping for $20, a few other small misc. items, and I was set to go.
I compare it to making soup--you can buy broth to make a base for your soup, or you can simmer a ham bone or something like that and make it much tastier. Same thing with beer--you can use the pre-made and concentrated extract, or you can make your own. It only adds another hour or so to your brew, and its not tough at all. Here are some great instructions. Have fun!
Used to ride the highway, used to know where I was going...but now this shady dirt road feels cool beneath my feet.