I see all these apps that can be downloaded by scanning a barcode. The question is, how do I actually do this? What app do I use to scan the barcode and install an app?
I prefer Google Goggles (available in the Market) for QR scanning to download an app. The most recent version now "sees" the QR and automatically captures it (older version required you to snap the picture before it is processed), then presents a link to the market.
Barcode Scanner is the best, you can also create QR Codes to share with others on their website.
QRDroid does it for me. It gives you lots of options to share the scanned data, and even does the opposite (generate a QR code out of an URL or text, for example).