OK, did a lot of research today, but unfortunately wasn't able to solve the problem. I'm close, however.

All preference information, including logon information, the machine ID, and preferences like running as a screen saver or not is stored in the CS.UD file in the WorldCommunityGrid directory. This file apparently stores it's data as XML, but the file is compressed and/or encrypted, thus you can't see the settings. This file constantly changes as UD.EXE does it's job, indicating it stores state information like the current work unit progress, etc.

I was also able to determine that there is some type of automated installation mechanism supported by the UD client. If you install WCG and pause at the "Installer has finished installing WCG on your computer", and look in the WorldCommunityGrid folder, there are only 3 files in there: UD.EXE, UDAGENT.HLP, and INIT.UD. The INIT.UD file is the key. It contains the following:

<settings>
use_proxy=0
referred=xxxx
auto_register=0
run_as_screensaver=0
connection_type=8
</settings>

(The "referred" parameter is a 4 digit number. I replaced it with x's because I believe it's machine-specific).

I figured that there should be some options that could be placed in this file which would allow an automated installation of the UD agent. To find out what they should be, I unpacked the UD.EXE executable and took it apart with a PE disassembler. The packing is an unknown format, and no ordinary PE explorer could find out what was going on. I eventually looked at the modules that were loaded into memory while it was running, and searched for the strings that would parse the INIT.UD file.

There are apparently MANY options that can be used here, I found them in the code. Here are the ones that might be relevant:

username=xxxx
password=xxxx
hostname=xxxx
auto_register=1

Under a normal 1st-time start of UD.EXE, the INIT.UD file is read and parsed, then deleted. Then UD.EXE creates UDTAPI.DLL in its own directory. Then the CS.UD file is created containing basic default options, and then the logon dialog is presented. When that is filled out, CS.UD is updated, and UD.EXE proceeds to download the 1st work unit.

When I tried the above parameters in the INIT.UD file (in many various conbinations, variations, and orders), UD.EXE started up, parsed the INIT.UD file, deleted it, created UDTAPI.DLL and CS.UD, and then hung. It wouldn't download a work unit and didn't appear to be doing anything, although the UD.EXE process was still running. Apparently there is at least one parameter I'm missing out of the INIT.UD file that needs to be there, or there are some additional XML tags that need to be present other than <setttings></settings>, or the parameters have to be in some unknown order.

If the programmers would be so kind as to throw us a bone with a bit of documentation on the INIT.UD file options, a .VBS or .BAT file can easily be written to do remote unattended installations as a service, and I'll be more than happy to post the scripts and instructions.