They are in North Freeport surrounding the Tier 2 Guild hall. You will need to be 80+ to get PVP writs since the Battlegrounds are 80+ (Anything over 80 will be automentored).
I also just found a few in Neriak! Collecting the shinies in my favorite city so I can have my cultural mailbox. They are located right next to the mount vendor and research assistant. This makes me happy. [/geek]