Kryptonsite has the article appearing in this month's Wizard (#208), which has some info and some quotes from Geoff Johns about the Legion episode of Smallville coming up. There are no plot spoilers in the article.
There will be many things for a Legion comics fan to enjoy. "If you're a real, real Legion nut, you'll probably see far more than anybody else will," he says. "There's a lot of stuff in there. They mention Polar Boy's planet Tharr. There's probably more fanboy stuff in this episode than a whole season of Smallville."
..."The first scene with the first scene of Act I, which was Clark, Rokk, Garth, and Imra inside the farm house," Johns recalls. "It was surreal because I had watched Smallville for so long. It was like, 'Hey, check out the Legion's uniforms. How do they look? Check out Persuader. What do you think?' It was really rewarding because everybody was working so hard and kicking so much a--. I remember the first time a Legionnaire said something I was like, 'This is bizarre. I never thought I'd see a live-action Legion. This is awesome."