FileInfo.com - The File Extensions Resource

.APE File Extension

File Type 1	Monkey's Audio Lossless Audio File (Most common)
File Format	File
Common?	No
File Description	Audio file compressed using Monkey's Audio lossless compression algorithm; includes error detection and support for tags that store information about audio files. NOTE: The Monkey's Audio encoder is freely available and can be incorporated into other software programs; therefore, APE files may be created with other programs besides Monkey's Audio.
Program(s) that open ape files	Mac: SBooth Max; JMAC Java Monkey's Audio Decoder Windows: Monkey's Audio (MAC); J. River Media Center; Nullsoft Winamp with Monkey's Audio Plugin; JMAC

File Type 2	AVS Plugin Effects File
File Format	Proprietary File
Common?	No
File Description	Component referenced by the Advanced Visualization Studio (AVS) plugin for Winamp; used for creating programmable visual animations based on the music played by Winamp.
Program(s) that open ape files	Windows: Nullsoft Winamp with the Advanced Visualization Studio plugin

Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/ape