Amazon has a desktop reading app. Barnes & Noble has a desktop reading app. And now — or SOON (when they launch their new operating system this fall) — Apple's iBooks will have a desktop reading app too.
Readers who've bought eBooks from iBooks on their iPad, iPhone, or iPod touch will be able to access those titles on their desktop — and any eBooks purchased from the iBookstore on their desktop will be readable on their iOS device as well.
This is a big development for iBooks, as Apple recently announced that they control 20% of the eBook market — and greater accessibility to their catalog of almost 2 million books should only increase that share.
For more information about the new iBooks desktop app, check out this story from MediaBistro.