Users of Android-based smart phones have a QR Code reader built in, but there are litteraly hundreds of different QR Code readers available.
QRCodes4Homes.com recomends the free i-nigma Reader, QuickMark and BeeTag apps, but there are many, many more available.
Search the iTunes App Store, the BlackBerry App World or the Android Marketplace for “QR Code” and you will find one you like, we are sure!