FreeRIP MP3 Converter integrates a full featured MP3 Converter. In fact FreeRIP can convert from/to various audio format, like MP3, WAV, WMA, OGG and FLAC.
FreeRIP MP3 Converter is very easy to use: first of all you need to run FreeRIP MP3 Converter and switch it to Converter Mode. To do it simply select View->Converter menu option.
Once FreeRIP MP3 Converter is set in Converter mode, use the File->Add files to convert... menu option to add the files you want to convert to a different format. You don't need to add files of the same type, e.g. you can add a Wav file, a Ogg file and a Flac file and then convert them all to MP3 in a single run.
Once you added all the files you want to convert, select the right option in trhe Rip menu. E.g. select Rip->Convert selected tracks to MP3.. menu option to convert all the added files to MP3 format.
Related pages in FreeRIP Manual: Converting Files.