Need Utility for Extracting Domain accou

There's several ways of accomplishing this but probably the easiest is to use a VB script called listmembers.vbs that comes with the WIN2K ResKit(I think you can find it free on the Micro$oft site too). The syntax for the script, assuming you're running NT 4.0, will be something like this:
cscript listmembers.vbs WinNT://YourDomain /C:user > c:\users.txt

This will extract all users in your domain to a text file on your C drive named users.txt. If you're unable to find the VB script try downloading the program nbtdump.exe from Cerberus. It's a free utility that will dump the netBIOS info from a box and run a few security tests on it. What you'll be interested in will be the resulting security file that it creates which if you point it at your DC should have all of the user accounts in it along with some other interesting info. Good Luck.