Hi Teak :wavey:
I sometimes use Cheetah
Cheetah Audio Converter is a very useful tool for anybody who owns a digital music player and needs to change files into different formats.
The software can convert music between all of the following four formats: MP3, WAV, OGG and WMA.
You can select the quality for each conversion, so it is simple to create files that take up less space. Don't forget that once information has been lost in compression it is gone forever, so Cheetah Audio Converter cannot improve music quality.
The interface is simple, if not a little basic. Files must be entered into the program via drag and drop, and the output type selected from menus.
You can download it here
http://www.computeractive.co.uk/vnunet/downloads/2128754/cheetah-audio-converter I'm not sure if it can compress mp3s any further though, but then I thought that mp3 was about the smallest you could get away with anyway.