On a lot of systems these days you can run "vipw" to edit the password file and change the UID.
vipw will update the shadow password file too (if you use shadow passwords).
I have vipw (I'm running RH9) but it seems to be just a incantation of the vi editor that takes me through the files and allows me to edit them. /etc/shadow doesn't seem to have any uid/gid in there, but I could be wrong.
I think I smell an enhancement to vpopmail just waiting to happen. Wouldn't it be nice if I could specify the uid/gid when I run --configure?? I mean, that's kind of a grand assumption that every single user everywhere who installs vpopmail will always want the uid/gid to be 89.
Is your computer infected with a virus? Find out with a FREE computer virus scan from McAfee. Take the FreeScan now! http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963