Pushing Patches Across a Wide Area Windows Network?

meridian-gh asks: "Microsoft is releasing new patches and updates for their products continually. For those of us who have to deal with large, geographically diverse windows-based networks, managing patches can be a nightmare. You cannot trust the users to do it. Tools such as SMS and HFNetCHK Pro are neat, but incredibly expensive. Most free programs I have seen don't support Windows 98, which many of us are forced to deal with. My question is, how do you deal with the remote deployment of patches in a efficient (and cheap) manner?"