There are other how-to's and instructables on building kegerators - I'll go through one using a top-loading freezer as that's what I used and it seems to have worked quite well - converting it is quite easy, there's plenty of room inside and it's been great for the last 4 years.
My brother and brother-in-law (with whom I brew) decided we wanted a 2-tap system since we were already brewing 2 batches at a time and we liked the look of 2 separate taps, so that's what I'll be going through as well. You could just as easily go with a single tower with dual faucet.
If you're ready to take the next step then check out the supplies and equipment listed below and read on! Once you have all the equipment and tools, this should only take about an hour (maybe less) to get your kegerator ready. It will take a bit longer if you want to complete the extra bonus round integrated drip tray though!
-Refrigerator or freezer (we went with a top loading freezer - more room and easier to modify!) Specifically the Holiday® 5.0 Cu. Ft. Chest Freezer from Lowes
-Homebrew kegging kit* - we used a Dual Cornelius Keg System similar to THIS
-Tap handle(s) (we made a 2 keg, 2 tap system) THESE
-A few extra worm gear clamps (probably available from wherever you order your kegging kit from OR your local hardware store)
-Digital temperature controller (if you go with a freezer) like THIS
*You can break these kits down into individual components if you'd prefer to do it that way (possibly cheaper) For us it was just easier to get the kit and modify it for our needs. Also getting used kegs and gas tanks will reduce the overall cost.
TOOLS / SUPPLIES
-Drill and drill bits
-1" Hole saw to match tap pipe diameter (may be different for other taps!!)
-Small tube of silicone caulk
-sheet metal screws
-1x Poplar furring
-1.5" wood screws
-white paint + brush
-CAD drawing for laser-cut kegerator 'bar top' and drip tray