So of course I went ahead and upgraded my two Macs to 10.4.4 and my WordPress 2.0 and mySQL 4.1.15 systems stopped working with the can't connect to mysql datasource error.
To fix this, this is what I had to do on two machines running Mac OS X 10.4.4 (client, not server):
sudo cp php.ini.default php.ini
then edit the php.ini file so that the "mysql.default_socket" line is:
save the file
sudo apachectl restart
and my wordpress blog was back in action.
I'm not sure if this is some odd thing that just hit my two Macs, but thought this could be of some help to others.