wxLame is a front-end for the LAME MP3 encoder that permits simple MP3 audio conversions.
wxLame is packaged in a simple interface and includes options that permit efficient conversion of your audio files to MP3. It is a little limited as far as format types, for instance, you only have one export choice which is MP3, and as for input you can only process MP3, WAV, AIFF and APE file extensions. It does support drag n' drop and multi-file input.
wxLame offers mild configurations which can be performed from the settings panel. You can modify the bit rate, opt for CRC error detection, adjust the sampling frequency, and more. Once you are satisfied with your selections, all you need to do is hit encode or decode depending on the operation.