The app launched in the App Store today. It isn’t completely clear from the write-up but it looks as if you can purchase books directly from the app. Here is what the blurb says:
Login with your existing Borders.com account and download the ebooks you’ve already purchased at no additional cost
Read full ePubs and choose from the original publisher style or our hand-tuned optimized reading experience
The “I’m Reading” list gives you quick access to everything you’re reading
Organize your library any way you like – by title, date last read, or author
Skip ahead in your book with the Table of Contents page
It’s the Kobo app, re-branded.