well, I was in the same situation, although I quit about 6 years ago. I would say, be careful with what you say. Don't say you quit just 2 years ago but 5 years ago or else they'll think that you're still going to relapse. It's very risky, and I just mentioned it in passing rather than focusing on it. Yet, since you have some violations related to your drug use, you have no choice but to mention it and to make them understand that it's in your past, that you've overcome it, etc.Good luck.
one of the big things that i think i am going to focus on in my PS is how my former drug problem equips me to deal with people's doubts/fears/complaints with the legal system, and to be an effective advocate for them. i am fully recovered now, and i don't necessarily adhere to the idea that "once an addict, always an addict," so it should be pretty easy to point to things in my life that can show i've recovered.