The Elgato Turbo.264 is essentially a USB video card dedicated to encode videos to the H.264 codec. What does this mean in English? If you have an iPod, Apple TV or similar media device this will allow you to get your videos on it easier.
I recently purchased an AppleTV and love it however the process of getting movies converted for it would take hours (or even days in some cases) on my G5 iMac. Also the computer would slow down to a standstill during the encoding. With the Turbo.264 it handles all the processing work so I can use my computer without knowing anything is encoding. It is also much faster across the board.
To use it you just plug it into an open USB port and open the application and drag and drop your video (or DVD image) on the window. Select your presets or adjust it to your specifications and click start. When it is done it will automatically ad it into itunes. The videos look very good, maybe a touch darker than other methods but I can only see it in side by side comparisons.
This little gadget saved me from having to buy a new computer so I am very happy with it!