Nov 16 2007 12:02 AM DVDs for season 1 should be available at most local manga/anime shops. It is less likely but also possible that they may be at places like HMV or similar shops. They are also available online from retailers like Amazon. Season 2 is also available (or at least part of it) on DVD. Amazon lists at least 4 DVDs of the second season available but at $30-50 CDN each it may cost a bit to get them all.
@radz143: No new info on a third season. There are a couple episodes coming out later this winter but most likely not more than 3-4.
EDIT: I find it rather comical that this thread keeps getting revived every so often to ask for information when it would make more sense to use the second season thread since I'm sure more people frequent it.