is a prefpane. With SystemSound you can play sound without opening a application in the Finder. Like with system 7 sounds in Mac OS 9. You can also specify a startup or shutdown sound.
SystemSound plays: AIFF, AIFC, WAVE, MP3, MP2, MIDI, SD2, ULAW, MPEG4, WMA and system 7 sounds. It includes a app that converts system 7 sound to AIFF or WAVE.