Barcode & QR Code Scanner - A free app which allow to read and generate barcodes for Android.
ZXing - Barcode Scanner for Android
QuickMark - QuickMark makes everything possible.
MKH Barcode Reader - This tool can be used to scan QR codes on your PC or tablet. Note: a webcam is required.
QR Droid - QR Droid Zapper
QR-Code Generator - QR Code Generator lets you create memorable marketing campaigns with trackable QR Codes—designed by you.