Thanks for the contributions. I replaced the welcome.msg with your template with one very minor change (the default initial password is the $SID which for many people is the same as the $LOGIN --- you just copied what was in the original welcome.msg).
You can use the rsync command to update the modelCourse. It would be cleaner to first mv (or rm) the current modelCourse directory.
The new directions for installation are at http://webwork.maa.org/wiki/New_Installation_Manual_for_2.4_on_Ubuntu_10.04
I just added info on editing the three new lines about the webserver in global.conf. They already tell people to add all the modules check_modules.pl finds except tth. Once WW 2.4.9 is released, I'll update it for Ubuntu 10.10 and put it in a more prominent place.