VLC is one of the most popular video players out there, but apparently not popular enough to avoid some issues with the Apple App Store. It seems that its maker, Videolan sent a copyright infringement notice to Apple recently concerning the iOS version of the video playing app.
As you might already know, VLC is distributed under a GNU General Public License (GPL), meaning that the software is open source and free. This goes against the restrictive policies of the iTunes App Store, so the control is too tight for the GPL regulations. Videolan has notified Apple and apparently the one to blame is the mobile apps developer Applidium.
They ported and published the app to the App Store, although they knew about the GPL conflict before submitting the software. All we can do is recommend you get the app from here, while you can.