I believe in order to download the game early you have to pay the $5.00 early access fee which gives you a few days head start and the ability to download the 13GIG client.
My brother has been downloading it for the last few days....I suspect its because it is due to his crappy DSL but it could be because of the larte number of folks download an extremly large file.
As far as the PVP server goes I am not a 100% sure how it works other than the PVE server has PVP zones set aside other than the PVP games where as I believe the PVP server has more zones available for open world PVP.
BTW I liked old school UO PVP I actually quit when they created the "other" non PVP world for everyone to play.
Probably another reason why I liked Shadow Bane, horrible graphics, horrible controls, great consept. Guild towns open PVP with the ability to loot corpses yay!