lame and linux!

Hello,
I'm new to the list, and new to lame, but i love it so far!! it's exactly
what we need for our web site.

I'm posting because I'm wondering how this can be done.

I've got about 30 gig's of mp3's on our web site ( all legal! ), all the
mp3's are in folders for the bands they belong too, we'd like to enable
on-demand streaming in a lower bit rate then when the use has uploaded, as
such I've added code to re-encode mp3's as they are being uploaded, but all
for the existing mp3's, is it possible in the Linux shell to use maybe grep
or something to go though all the folders and re-encode every single mp3 one
at a time using this command
 lame -b 64 -f -m s SongName.mp3 stream_SongName.mp3
of course replacing SongName with the actual song name. and also have them
placed back in the folder where the original file was?

hope you guys understand what I'm saying here. any ideas would be great!

thanks in advance for your time,
-Ken