Following on from the success of the Xbox 360 multiplayer events, Rockstar will be hosting another multiplayer event on Friday, 5th February (tomorrow) from the usual 4PM to 7PM Eastern Time, this time on the PS3. A PC event will be coming up soon, and there will be a whole calendar of events announced next week! So stay tuned for those.
Full details of how to get involved in the event can be found on the Rockstar Newswire
That trophy/achievement is viral so you just have to kill someone who has already got it. Pretty much everyone who's ever played online has it because it spread so quickly.
So you don't have to shoot an R* staff member online just to get that, right?
I was there, and owned the hell out of RockstarMulti1. I was running him over, shooting him with the automatic pump action glitch... it was lots of fun. The best part was when they invited me through the whole time ( I played about 14 matches with them, since they stayed an hour later).