Audio/video format developed by the 3rd Generation Partnership Project 2 (3GPP2); designed for transmitting multimedia files over the Internet; basically an updated version of the .3GP format used by cell phones for saving video files.
Program(s) that open 3g2 files
Mac / Windows: Apple QuickTime Player; VideoLAN VLC media player
Unix: VideoLAN VLC media player
Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/3g2