+1 or not wasting time on ab exercises - that's not how to get a 6 pack. It's as simple as drastically altering your diet to get rid of the layer of fat covering that potential 6 pack. Body builders use nasty shit like 'fat burners' to do this, but I've seen junkies with equally ripped abs. Starve yourself, get addicted to heroin and run around like a mad dog looking for drugs all the time and you'll get there pretty quickly.
The only person I know who has a 6 pack has a totally carb free diet, eats lots of meat, does lots of cardio, doesn't drink alcohol and is know to sit around munching on spinach straight out of the bag for a snack... As well as a 6 pack he also rocks chicken legs...
Personally I think 6 packs looks pretty hideous and insectoid-like, but that's just me. I've heard that chicks don't really dig them all that much either.