1- How does the "world pass" system work, exactly?
You inster a code while creating your character that allows you to choose your server. Get the code from friends that your joining.
2- When I pick an advanced profession, do I lose my original job?
Nope, it becomes a sub-job. The 2nd job isnt quite as powerfull as your main.... ask bohica im no expert here
3- can I have both a second profession and an advanced profession?
no, you can only ahve 2 jobs. 1 Main, 1 Sub.
4- Any PSU style site for it? With newb guides and such?
Umm yeah, i few I suppose, Allakhazam (
http://ffxi.allakhazam.com/ ) has a nice site. (PM me and ill try to get u more links) If your going to play on Kujata (with PSU and BOHICAns), im sure you can get help