ZXing (pronounced “zebra crossing”) is an open-source, multi-format 1D/2D barcode image processing library implemented in Java. Goal is to use the built-in camera on mobile phones to photograph and decode barcodes on the device, without communicating with a server.

This library is divided into several components of interest:

core: core decoding library, and the main component of the entire project
javame: JavaME client
javase: J2SE-specific client code
android: Android client (1.0 SDK)
androidtest: Android test app (1.0 SDK)
rim: RIM/Blackberry-specific client build
iphone: iPhone client + port to Objective C / C++ (QR code only)
zxingorg: The source behind zxing.org/w
bug: Client for BugLabs’s BUG

http://code.google.com/p/zxing/