Although personally I am comfortable with doing my conversion work by hand at the CLI console, MHAC might appeal to those looking for a GUI based solution.
MediaHuman Audio Converter is a freeware application for Mac OS X and Windows. It can help you to convert your music absolutely free...
A couple of notes about MHAC's portabilization: the installer downloaded can be easily (Uni)extracted, so no need for the install/unistall cycle recommended by rbon; as for the the 'custom.pf' file mentioned, any empty text file with that name will do; lastly, there's a ready made yaP launcher available from http://rolandtoth.hu/yaP/#examples.
MHAC is in active development and the latest release (currently v184.108.40.206) cand be downloaded from https://www.mediahuman.com/download.html.