Update: Running Icecast and MPD on the same NSLU2 may not be the best idea, at least if you're going to use the stock config files. I'm seeing almost 100% load on the box and the output to another system is quite bursty (about 3 seconds of silence for every 3 seconds of music). It's probably a good idea to put the utils on different systems (2 NSLU2s or a NSLU2 and a full-size computer?)(works nicely if I use my Asterisk service as a source). As I've built this for someone else, I don't have the resources (okay, or motivation) to tweak these.
For anyone that cares to, I will offer an account on the wiki if you'll post your tweaks.