ZXing - Barcode Scanner for Android
QuickMark - QuickMark makes everything possible.
QR Droid - QR Droid Zapper
Barcode to PC: Wi-Fi scanner - Turn your smartphone into a real barcode scanner
ConnectUpz - Helping service businesses to connect and grow your customer base by becoming part of of a larger ecosystem.
MKH Barcode Reader - This tool can be used to scan QR codes on your PC or tablet. Note: a webcam is required.