Monkeys Audio

Monkeys Audio is a fast and easy way to compress digital music. Unlike traditional methods such as mp3, ogg, or wma that permanently discard quality to save space, Monkeys Audio only makes perfect, bit-for-bit copies of your music. That means it always sounds perfect – exactly the same as the original. Even though the sound is perfect, it still saves a lot of space (think of it as a beefed-up Winzip™ your music). The other great thing is that you can always decompress your Monkey's Audio files back to the exact, original files. That way, you'll never have to recopy your CD collection to switch formats, and you'll always be able to perfectly recreate the original music CD.

Features:

Efficient (fast and great compression) — Monkey's Audio is highly optimized and highly efficient
Perfect sound — absolutely no quality loss, meaning it sounds perfect and decompresses perfect (it's lossless!)
Media Center™, Foobar™, WMP™, Winamp™, and more support — supported by most popular players and rippers
Easy the Windows environment interface is both powerful and easy to use
Free