Songbird from http://getsongbird.com/ is a media player. It plays audio but will in future also play video. Songbird gathers together a disparate range of features from across the Internet and plugins to provide a media player that enables "new ways to playback, manage, and discover music".
Songbird is cross platform, possibly free open source([http://blog.songbirdnest.com/2005/11/28/songbird-license/ ?) software, based on Mozilla software.
http://wiki.songbirdnest.com/Release_Notes Release Notes for all versions
Installer Command-line Switches
/S - install silently