Rogue Traders are what GW calls store held tourneys. They use the current rulebook.
'Ard Boyz tourneys are held once a year around the country. 2500 pts. If you place in the top 3, you advance to the next round which is held about a month or so later. If you place in the top 3 of that round, you advance to the finals held in Baltimore a month or so later. If you win that, you're pretty much considered the best 40k player in the country. The chapter master of our gaming club, (the Hellfish) Kevin Kirby, won it 2 years ago (2007) with 'crons. Got his pic in the White Dwarf and won tons of prizes.
It's a great time!