Tor have just announced that they have their own ebookstore inside of iBooks. It's going to be stocked with a curated selection of Tor-Forge titles and it will be updated monthly.
I'm glad they announced it; I can't find their section of the iBookstore. In fact, I can't find even a hint that iBooks has branded storefronts. If it's there, it's really well hidden. BTW, now that I have a reason to dig through the iBookstore, I have to say that I'm surprised how broken it is. I've found several authors who will turn up in a search but are not listed in the index. Strange.