wntipcfg.exe
The Tip that made me download wntipcft.exe:
How This Tip Works
Instead of using the command line to display /configure your ip with ipconfig, you can download wntipcfg directly from Microsoft which will give you the same GUI to display / configure your ip as winipcfg.
Download: http://microsoft.com/windows2000/techinfo/reskit/tools/existing/wntipcfg-o.asp
When you have downloaded it, install it (the default is c:\program files\resource kit\ ) copy wntipcfg.exe to c:\windows and rename it to winipcfg.exe Now you can just click on run, then type in "winipcfg"
I always wondered why Windows XP didn't have a version of winipcfg. After downloading wntipcfg and trying it out, I guess I understand why the command line is better.
I ran into the following errors with the program:

Could not read EnableDHCP flag
followed by

Fatal Error Inconsistent registry contents
The problem was that I had two interfaces going. A media-disconnected local area connection, with a static IP address and a dialup connection with DHCP. At first I thought the error was because I had one static and one DHCP interface, but that wasn't actually the problem (and giving that a little thought, why should it be?).
The actual problem is that wntipcfg.exe won't run while connected to my dialup. If I disconnect and run it, it works ok, to some extent. It has the look and feel of Windows 98's winipcfg, but is somewhat annoying. For instance, from a CLI, an ipconfig /release on an interface that isn't capable of releasing its IP address will give you a simple message:
Microsoft(R) Windows DOS
(C)Copyright Microsoft Corp 1990-2001.
C:\>ipconfig /release
Windows IP Configuration
The operation failed as no adapter is in the state permissible for
this operation.
But the same scenario in wntipcfg.exe will give you either a fatal error or have the boxes grayed out so that you can't even attempt to renew or release them. Yeah, I know when an interface isn't going to be able to do a renew, but I sometimes like to run ipconfig /renew as somewhat of a Hail Marry command.
Anyway, a dial-up connection must lock the DHCP flag so that it can't be released while you are online. Which makes sense, because releasing an IP address while connected to a dial-up ISP doesn't sound like something you really want to do.
At first I thought bug, but now I'm more inclined to say just quirky. Given that in all of the Internet, there were only 49 links to people posting about this error, I figure quite a few people were able to figure it out on their own (or all 49 people who downloaded this tool experienced the problem <g>). Still, I didn't find anything at Microsoft specifically about this issue. It would have been nice to provide an explanation for a problem that a lot of people that actually try wntipcfg.exe might run into.