If I did the PSN preload for this game, would I be able to play as soon as it's done downloading? how does this work? what time would I be able to play? I live in US central timezone. Thanks.

Pre-load just means that you can buy and download the game right now.
You won't be able to play the game until it is released and available to everyone.

Most games even come with a timer countdown, so you can keep track of the very minute the game will "go live" for you and be ready to play.

Can i pre load for PC (steam)?

ok thank you, I think I will just wait until tomorrow when I can go buy it, I just like to have the disc more than a chance to play a little early, Ive been waiting months for this game, hope it is amazing!