Trying to download book from iBooks. iPhone

Im trying to download a book from iBooks (latest version) on my 3Gs (latest software). The book is Matthew Reillys Seven Deadly Wonders.
When tapping on it to go to the download page in iBooks it takes quite awhile and then takes to a screen that says, Seven Deadly Wonders is available for download in iBooks.
But no Buy button. Just buttons, Learn more about iOS 4 and Learn more about iBooks
Anybody else see this?
MacBook Pro 13" 2.26GHz Mac OS X (10.6.4) iPhone 3Gs 16GB, iPod, iPod Hifi