QR Codes are those two dimensional black and white codes like the one to the right. They look rather confusing, but pack a whole lot of data. For example, the one to the right contains the data "market://details?id=com.kmagic.solitaire". So, you may ask what’s the big deal and why do you see them everywhere on Android sites? Well the good news is that if you see an app you want to install on your Android phone, you don’t have to search for it in the Android Market. You can just point the camera in your Android phone at the QR code and it will point your directly to the app page in the Android Market.
To do this, you phone will need a little help though. You can use Google Goggles for example to do this. Search for Google Goggles in the Android Market and install it. Then, once you have Google Goggles, or another QR code reading app installed, just point it at a QR code and it will decode it for you. A very easy way to get apps onto your Android phone.