Librarything.com

Search for an iphone scanning app

and import the barcodes

https://www.google.com/search?q=scan+many+isbn+numbers+at+a+time#q=scan+many+isbn+numbers+at+a+time+iphone
 * https://itunes.apple.com/us/app/bakodo-barcode-scanner-and-qr-bar-code-reader/id371932548?mt=8