Programs that support Monkey's Audio
JRiver Media Center : the best player and secure ripper around, with seamless APE support
foobar2000 : a simple yet powerful audio player
Exact Audio Copy (EAC) : the best ripper around...guaranteed perfect rip... come on, you owe it to yourself
dBPowerAMP Music Converter : great tool for converting to and from a ton of formats (including APE)
Winamp : the player that needs no introduction
Easy CD-DA Extractor : an excellent CD ripper (and more) with Monkey's Audio support
Audacious Media Player : a popular open source audio player
fre:ac : a great program for converting audio written by a great guy that's been a huge help (it works on Windows, macOS, Linux, and FreeBSD).
Strawberry Music Player : a free program aimed at audiophiles.
AIMP : a powerful free audio player for Windows and Android. Additionally, it includes powerful tools to operate with audio files (tag editor, audio converter).
Pure Audio Player : a lightweight audio player for Windows with APE support.
Lossless audio compression sites
Sites that list Monkey's Audio
Wikipedia: Monkey's Audio information at Wikipedia
Codecs.com : lots of media related downloads
Softpedia.com : download site that lists Monkey's Audio
Radified Guide : a guide about ripping and encoding
FileCroco : handpicked software for a Windows PC
Software Informer : another download site, which seems to like Monkey's Audio :)
Kuba Download : a great download site that lists Monkey's Audio
BytesIn : a download site that lists Monkey's Audio with downloads, guides, and reviews
Soft Online : free software downloads for PC and Android APK, with a nice Monkey's Audio review