Have you ever needed to know the address of your DHCP server? I don't know how useful this will be to people, but it was surprisingly tough for a team of three of us to figure out, so I figured it's worth a post. Surprisingly, the address doesn't show up in the system log, ifconfig, NetInfo, or anywhere else that we thought to look (and we looked in quite a few places)!
So here's the solution,. Go to the Terminal and run this command (replace en0 with en1 if you're on AirPort):
ipconfig getpacket en0
According to the manual page for ipconfig, this command appears to be unique to Mac OS X, first introduced in the Public Beta! The command will display a bunch of useful info, including:
Mac OS X Hints
http://hints.macworld.com/article.php?story=20060124152826491