12-30-2011 02:13 PM
First, be aware that "transferring" a book---even if you do me making a copy for yourself and deleting a copy from the other device---may be a violation of the DMCA and/or other applicable copyright laws.
That said it is fairly easy, though you will need access to a computer and a USB cable.
Get the file onto the computer. If you're dealing with an N1E or sideloaded content on any other device, it's a simple drag and drop of the file. If it's downloaded content from B&N, it will be hidden in the partition. The easiest way to get a copy then is to download from the other user's B&N account (either directly or via Nook for PC.)
Once you have a copy on your PC, it's a simple matter of attaching your device and dragging and dropping the file to your device. If the item is DRM'd (via B&N's social DRM) you will need to enter the original CC# and name associated with it to unlock the item. If the person will trust you with that.
It gets more complicated if they purchased DRM'd content elsewhere. Then you may have to try removing the DRM, which specifically is a violation of the DMCA. If you feel the need, google it, but I have not done it nor can I advocate it in your scenario.