Quick example of how I linked our SharePoint website to a barcode scanning app called Zbar. This effectively turned our SharePoint website into a database that we could access with our iPhones. You just scan the item, pull it up on the phone, adjust the details, and save. Works with many types of barcodes including QR codes.
This can be used to verify products on the jobsite match submittals, and it can be used to track workflow and installation status of materials.