It's becoming hard to differentiate all the YouTube converters we find these days. TubiTunes isn't much of an exception and will offer the typical drag and drop and convert.
The application lets you select any video you find on any video sharing site like YouTube and DailyMotion. Drag it onto TubiTunes' interface and the program takes of converting it. iPhone is the default destination format, yet you can also have it convert for the iPod or Apple TV. Digging in the preferences you'll see you can choose the destination for the converted video, among which you can create a playlist in iTunes just for your TubiTunes files.
I was pretty disappointed by TubiTunes as it failed on each and every single video I tried to convert. Similarly I was disappointed not to find a progress bar, as conversion can be a bit slow and I like to know how much time the task will take.