Thanks for the tips John; I got it working shortly after I wrote this post; I was trying to accomplish too much with my php.ini; I was adding a bunch of other extensions into it that weren't loading..
After I simply added the line:
extension = php_oci8.dll
and rebooted, all was well. PHP has been remarkably simple, all in all, since we're coming from a strictly IIS4/StoryServer 4.2.6 implementation. Their ISAPI filter, iis4curl.dll, fails to load every so often, for no rhyme or reason, and of course they want many thousands of dollars for support!
My implementation is this:
Web server(s): PIII 500, 128MB, 18GB disk space, Windows 2000 in Active Directory native mode, IIS 5.0, Windows Media Services, latest version of PHP. Multiple web servers with directory replication and DNS round-robin for the cheapest failover without doing clustering or Windows Load Balancing Service.
Database server(s): Dual PIII 550 Xeons, 256MB, ~50GB disk space, Windows NT 4.0, Oracle 8.0.5
Thanks all!