fre:ac - fre:ac is a audio converter and CD extractor designed for Microsoft Windows, Mac OS and Linux, distributed under the GNU General Public License.

LameXP - LameXP is an Audio Encoder Front-End, a graphical user-interface for a number of audio encoders.

winLAME - winLAME is an encoder for several audio formats, including mp3 (MPEG Layer 3), Ogg Vorbis and more.

FLAC Frontend - [No longer maintained, but downloadable]

LameDropXPd - LameDropXPd is a practical frontend for LAME that makes things easier to the user, as there is no...

SoundConverter - The sound conversion application for the GNOME environment.