Hi Scott,
noticed you had a faq on your twiki:
http://www.atomicorp.com/wiki/index.php ... to_postfix

I found that my plesk.repo indeed has "exclude=psa-mail-driver-qc" in it, however when I run yum, it seems that its named slightly diff:

Installing:
psa-mail-pc-driver x86_64 1.0.0-cos5.build92091210.17 plesk 1.8 M
replacing psa-mail-qc-driver.x86_64 1.0.0-cos5.build92091210.17


i changed it to exclude=psa-mail-* to prevent this from happening, but perhaps that's too heavy handed?
Do i need to exclude both, or just psa-mail-pc-driver (is this postfix, which I dont want?)

That approach is indeed too heavy handed. You've excluded both qmail and postfix like that.

pc = Postfix
qc = Qmail

Pick one and exclude the other. If you don't exclude any then one will "upgrade" over the other every time you do a yum update.