One of the neat things that can be done with smart phone applications is storing barcodes.

Other smart phone applications can read barcodes.  Put the two together and you get

The pictures show iSpydus (one of Civica’s smart phone apps) selecting a borrower by reading a barcode from another phone.  The user can now issue books to the borrower using iSpydus to scan the barcodes off a book or other library item.