Lots of info in the bottle/kegging section.
If you have an old fridge you want to convert then you should, but if you are starting fresh you should look at the 'sizing your chest freezer' or whatever it is thread in the sticky of that section. It will show how many kegs a chest freezer holds.
Lots of people have converted fridges, but the general consensus seems to be chest freezers hold in the cold when you open them and seem to allow for more kegs/taps in a smaller space.