Here is the portable version of iTunes.
What is iTunes? It is the official player program from Apple to play, synchronize and buy your music and videos, etc.
It allows you to have all of your multimedia content well organized and synchronized across all supported devices. And, in iOS and Mac you will also have a lot of exclusive audiovisual content...including personal recommendations and personal features for music streaming services.
You can also find iTunes in the app store for iOS devices.
This version of iTunes is portable, which means you do not need to install it, and you will be able to carry it with you on any pendrive.
The iTunes Portable version does not correspond with the latest version of the official iTunes client (11.0), but with the older release (10.6).
If you want to have iTunes with you on any computer and be able to access your content from anywhere, iTunes Portable is the nonofficial solution that offers you the tool you need...as well if you want to have an older version of the releases that are offered from Apple.