Usually, when I need to convert many wav files, I'll use a perl script I wrote - its on the Helpfull Apps Page. But today, I didn't care about ID3 Info or anything like that. I use LAME for commandline encoding and here is the one-liner that took care of the directory:
find ./ *.wav | sed 's, ,\\&,g'| xargs -n1 lame -b -96
