Recording / Playback
* Several bugs fixed so that latency correction should be better, and more devices work correctly.
* Problems with invalid sample rates under Linux should be much rarer.
* Newer version of Portaudio library.
* New feature to record onto the end of an existing track (hold Shift while clicking Record).
Import / Export
* Updated versions of Libogg, Libvorbis, Libflac, Libsndfile and Twolame libraries.
* Handling of unsupported file formats more informative.
* Handling of file names with slashes on OS X improved.
* New dialog allows replacement of illegal file name characters on all platforms.
Interface
* Improved scaling and layout for rulers and VU meters.
* Envelope fixes/improvements including full control of undo/redo.
* New keyboard shortcuts and improved menu navigation.
* Preferences:
o More intuitive tab arrangement.
o New options for mute/solo and Metadata Editor behavior.
o Language can now be changed without restart.
* Expanded Build Information tab.
Effects
* New Vocal Remover plug-in, improvements for Generate effects.
Compilation
* Fixes when building Audacity with libraries disabled.
* Improvements to make Mac and Solaris builds easier.
Security
* Full fix for issue CVE-2007-6061 on systems where temporary directories can be changed by other users (thanks to Michael Schwendt).
Miscellaneous
* Updated translations for many locales.
* Several stability improvements.
"Audacity is free, open source software for recording and editing sounds. It is available for Mac OS X, Microsoft Windows, GNU/Linux, and other operating systems." Via