Audacity is a cross-platform audio editor/recorder/converter. It's open source and free for one but it's also very flexible. You can record & play sounds, import and export WAV, AIF, MP3 and more formats. It's a multi-track editor as well that lets you mix sounds together and apply effects to your recordings. For those wishing to capture from LP (vinyl), you can remove hiss, static and hum and other background noises. It also has a built-in amplitude envelope editor, a customizable spectrogram mode and a frequency analysis window for audio analysis applications. Built-in effects include Bass Boost, Wahwah, and Noise Removal, and it also supports VST plug-in effects. You can cut, copy and paste and still have unlimited Undos.
Mac OS X 10.4 PPC, Mac OS X 10.4 Intel, Mac OS X 10.5 PPC, Mac OS X 10.5 Intel, Windows 7, Windows Me, Windows 98, Windows 2000, Windows Vista, Windows NT, Windows XP