Using the Windows “command line” (DOS, or in XP “not DOS”), you can get a nicely formated printout of your Network configuration by typing the following command.
OS X, surprisingly, lacks a similar command. This thread over at OS X hints lists the several different commands you need to run in order to collect the desired information. I am archiving the useful bits here in case the OS X hints thread vanishes.
The most important of those is the DNS server. For some reason, when you’re using DHCP the Network preference pane doesn’t list this important bit of information.