OK came across this on SinfuliPhone :
You need to use Stanza for this.
Just add [Only registered and activated users can see links. ] to your book sources in Stanza. You can call the source whatever you want.
Once saved you can access the source and Viola you have a shit load of books that you can download directly to your idevice. Just d'loaded all of David Gemmells books which I do own on Hard/Paperback anyway !