The PvP rules are spelled out here:
http://eq2players.station.sony.com/en/news_ff.vm?FeatureName=pvp_combat§ion=development
Unlike EQ1, there is only one PvP ruleset.
There are no rules or changes to the way the server works specific to Roleplaying, they just want people who want to join others who enjoy roleplaying. It's not required, but it's encouraged. People who roll on an RP server just to make fun of roleplayers are R-Tards and should stick with WoW. (I tried an RP server there and it was a constant problem.)
As far as what you can and cannot do on a regular server, well, that's a pretty broad question as it encompasses the entire game. Is there something specific you want to know whether you can or cannot do?