Audacity is a powerful audio editing/recording software package that doesn’t require much training. It works on Linux, Mac and Windows, and it handles many file types, including OGG, MP3, AIFF, AU, and WAV (but not WMA or AAC). Its features include 32-bit/96-KHz recording and editing (up to 16 channels), independent speed and pitch control, noise removal, a spectrogram mode, and tons of built-in effects. But it’s also perfect for quick recordings and editing long files.
Get it here: http://audacity.sourceforge.net/