Making a keggerator or keg fridge at home is rather simple as long as you have a spare fridge to play with. There are a number of people selling fridges in classified ads and at garage sales for $40 or $50 so look there first.
I purchased a keg fridge kit off of a seller on eBay. In total it cost me $350 and as you can see from the pictures below it included two kegs, a 5lb CO2 tank, 2 taps, and all the hoses and clamps.
Once you’ve picked the kit that you want and you have a fridge to use you simply have to drill two holes through the front of the door using a hole saw drill bit. You should make sure before you drill the holes that your fridge does not have any cooling coils running through the door or your fridge will end up being a piece of junk. However, most fridge doors are just filled with insulation so you should be fine. Another thing to note is the placement of the tap holes. If the holes are too low you will be on your knees pouring the pint. If it is too high and you try to open the freezer door it will hit your tap handles and all your precious beer will be on the floor. You can see that I no longer use tap handles because of this problem.
Now that the tap handles in you can screw on the hoses which connect to the kegs. The kegs are actually old Pepsi canisters that used to be used to for fountain pop. Today pop companies use plastic bags so all of these kegs are useless to the pop industry and are being snatched up by home brewers. The kegs hold about 20L and have an In and Out valve. The CO2 attaches to the In valve which carbonates the beer and helps push it out the taps. The hose to the taps is connected to the Out valve and when the tap is opened out comes the beer!
The disadvantage of this system is if you do not make your own beer then it might not be worth your while. You could not order a keg from the Beer Store and set it up in your fridge because “real” kegs have different attachments so you wouldn’t be able to connect it to your taps. However if you are a home brewer then this system is great. I originally wanted to have two flavours of beer at any time, but found I was drinking far too much. So now I only make one keg and put lemon water in the other keg. The CO2 carbonates the water so I have a tap of sparkling lemon water and a tap of beer.
Now if you are not interested in all this do it yourself home beer stuff then check out Barfly for some absolutely stunning retro beer fridges.