I find it strange/annoying they haven't implemented a guild/group joining system for pvp. I assume it's something they will introduce at some point though as it essentially renders guilds pointless apart from being a social hub which will nice, isn't really their point. (well their main point)
They have you need the commander badge. and you can click on anyone name if they in your friends list and say join in pvp.
On another note, dinged 80 today
