Well after a looooong weekend, countless hours going back and forth with SWSoft's support team, I've unfortunately discovered that Plesk 8 does not work on any new Intel Macs.
Their auto-installer runs and the tar.gz files unpack, but there isn't an accessable psa.inf3 file. The SWSoft software developers blame the problem on a "system_calls" file difference (whatever that means). I double checked that I was doing the install procedure right on my iBook -- yep, installs great -- but definitatly does not work on any Intel Mac.
I've spurred change with SWSoft though, I got them to put "PowerPC only" on their Plesk 8 requirements page -- but they are digging in their heels and resisting giving me a refund for the license we purchased. Has anyone else had a similar experience and found a work around on their Intel Mac?
The most infurating part of it all was, I asked the sales department if it was compatible and they had no disclaimers prior to my rattling nearly every cage in the place.
So be forewarned -- SWSoft Plesk 8 does not work on ANY Intel Mac.