QR code stands for Quick Response code. They are similar to Bar Codes. Bar codes are linear one-dimensional codes and can only hold up to 20 numerical digits, whereas QR codes are two-dimensional (2D) matrix barcodes that can hold thousands of alphanumeric characters of information.
You can scan or read a QR code with your iPhone, Android or other camera-enabled Smartphone, you can link to digital content on the web; activate a number of phone functions including email, IM and SMS; and connect the mobile device to a web browser.
How does the cell phone read the code?
Where to find QR code reader’s software for my phone?
You can get various softwares for your phone to read/scan QR codes.
Android Devices:
https://market.android.com/details?id=com.google.zxing.client.android&feature=search_result#?t=W251bGwsMSwxLDEsImNvbS5nb29nbGUuenhpbmcuY2xpZW50LmFuZHJvaWQiXQ
Apple Devices:
http://itunes.apple.com/us/app/qr-reader-for-iphone/id368494609?mt=8&ign-mpt=uo%3D2
Blackberry Phones:
http://appworld.blackberry.com/webstore/content/13962/?lang=en
Nokia Phones:
http://store.ovi.com/content/231518?clickSource=search&pos=12