A heads-up that may be useful to others: it's moved in Leopard.
By coincidence, it was two audio programs that alerted me to this. I just updated VLC (now at version 0.8.6d) and Media Rage (now at version 3.3). Afterwards, the "Open With" dialog on audio files had multiple instances of both programs. This is something I've never had a problem with before but which I knew the fix for. The fix is to rebuild the Launch Services database.
But it turns out that the path to lsregister is different under Leopard. Turned this up by Googling:
http://www.macosxhints.com/article.php? ... 2084155353