The great Charlie Papazian said that this little tool was invaluable in making the most tedious part of homebrewing a bit more enjoyable. For several months I told myself "it's just a little more work to wash them with a brush." I will have to live with that regret and lost time for the rest of my life! Cleaning 60 bottles now takes about 10 minutes. For truly effortless cleaning, just make sure you rinse out the bottle right after you drink the beer, then when you go to clean them before bottling you wont have much to clean. Just a quick soak in some warm water (soap or cleaner optional) and the jet does the rest! Amazing and only $15 or so. I picked mine up at Keystone Homebrew.
It screws right onto any faucet with a hose thread. My utility sink is perfect for this kind of work.