Audio to MP3 Converter can convert AAC, AC3, AU, WAV, MP2, AIFF, FLAC, OGG, WMA, APE to MP3 format.
To use, just select the tracks you want to convert (Audio to MP3 Converter includes a batch convert function), and select one of the presets. The presets range from 96 - 320kbps and will let you determine the quality of the converted audio.
Audio to MP3 Converter has a simple, easy-to-use interface that will let you convert your files in a few clicks. That said, it looks terrible, and there's not much you can do to change that, as it only includes 5 uninspiring skins.