If you visit the SciFi site for Battlestar Galactica, there’s a banner across the top that says you can buy episodes from iTunes. When I clicked on it, it opened iTunes and displayed all the episodes for Season 2 for $1.99 each. It had all of them through last weeks. I believe the episodes are available the next day (Saturday).
BTW, I came across an interview with Ron Moore on the Chicago Tribune website. There’s some interesting information about the upcoming episodes (spoilers).