I use sample manager

http://sox.sourceforge.net/

Thanks for the advice guys. In the end I used this utility - it's free for under 500k file sizes, but I bought a license anyway. There's a Windows version as well. Does the job quickly, simply and (as far as I can tell!) well.
http://dekorte.com/projects/shareware/SoundConverter/

Peak is awesome, but expensive.

If you do manage to get FFmpeg installed (You have to compile it from source, which I'm sure is scary for the average Mac user) here's a simple bash script that will convert all .wavs in the given directory to Uncompressed 8-bit PCM .wavs.

for f in *.wav; do ffmpeg -i "$f" -acodec pcm_u8 "${f%.wav}-U8.wav"; done

i use Bias Peak 4, does batch stuff just fine.

Doesn't iTunes do that?

You can use FFmpeg, it's free, and open source, then you could use a simple bash script to convert all the audio files easily.

Hello all,

Does anyone know of a free/cheap easy-to-use batch converter for audio files that I can use in OSX? A lot of stuff in my sample library is higher than 16-bit which means I need to resample before I can use in Piggy tracker, and the thought of doing each sample manually in Quicktime makes me feel slightly faint. Any tips for how I can automate this would be much appreciated!

Matt