SecScanQR - The QR-Code Scanner/Generator that cares about your privacy
Binary Eye - Binary Eye is a Free Open Source barcode reader/scanner and generator.
QR Droid - QR Droid Zapper
ZBar bar code reader - ZBar bar code reader
ZXing - Barcode Scanner for Android
NeoReader - The NeoReader is a universal barcode scanning app that transforms your mobile phone into a barcode scanner, allowing access to mobile web content by scanning codes from virtually any medium