Update: Seems like even five mill ain't gonna be enough for Apple, which is set to massively expand its iBooks user base by bringing the app to iPhone and iPod touch users. You'll be getting the same note-taking, same bookmarking -- same everything -- just on a smaller screen, and at no extra charge. Users will be able to purchase a book on one device and then consume it across the full range of iDevices, with bookmarks and progress getting synced across the ether.
iPad corners 22 percent of ebook market, gets PDF viewer
iBooks for iPhone
Check out more from WWDC 2010 in our liveblog!