Launched todaySo far US only but I guess they are trying to get it elsewhere soon. In a strange move, so far they can only be read on the PSP and need to be purchased through the PSP or the MediaGo PC client.
Anyway, I'm gonna check it out. I'm currently on the latest PSP firmware on account of LittleBigPlanet (no worries though, with my Pandora battery and magic memory stick I can be back on CFW in 10 minutes), and I saw the little "Extras" icon on the system. Below that is the Digital Comics reader. Its a separate download but only 5MB or so.
The store currently has something like 17 free comics you can grab to check the whole thing out. I lined up the few that looked interesting to me. Havent downloaded any yet so I'll report back when I do. One interesting thing I read today was that comics can have their own audio tracks and can have things like artist commentaries, similar to DVD commentary tracks. That'll be interesting.