The Pro Bundle is available as an in-app purchase from the free version of Winamp for Android, so you won't see it as a separate download in the Android Market. It adds a boat load of premium features to the free Winamp app. These include an EQ, Customizable Home Screen, Gapless playback, crossfading between track, additional SHOUTcast features... and more.
We plan on adding even more features to the Pro Bundle in the future, but for a full list of current features, read the v1.2 release announcement.
If you haven't already download the free Winamp for Android app (version 1.2 or higher required), download it from the Android Market.
From the free app's home screen click on the EQ button. Alternatively select "Go Pro" from the settings screen.
One part genius. Three parts llama. And a sprinkling of corporate AOL. That's what Winamp is all about.