SoundKonverter is a frontend to various audio converters, replay gain tools and CD ripper, using KDE platform.
There are different methods to converse audio files you can simply select files or a folder, add a URL and it will convert the this file to the output folder you desire.
Install SoundKonverter 1.00 in Ubuntu 11.04 Natty Narwhal
also this works on Kubuntu, Xubuntu as long as you have required dependencies.
Install SoundKonverter 1.00 in Ubuntu 10.10 Maverick Meerkat
Also check other download options for OpenSuse -11.4, Debian 5, and Debian 6 Here.