This is a MonoTouch binding for the ZBar iOS SDK which can be found at
http://zbar.sourceforge.net/iphone/sdkdoc/index.html
The current version of this binding is for ZBar iOS SDK 1.2
This binding hasn't been updated since the move from MonoDevelop to Xamarin Studio. If having trouble building via XS, see here: tystol#2
Otherwise, simply drop the libzbar.a file into the /binding directory and run the makefile or open and compile the ZBar.MonoTouch.sln
Simply drop the libzbar.a (make sure it has all supported architecturs lipo -info libzbar.a
It should output Architectures in the fat file: ../.lib/libzbar.a are: armv7 armv7s arm64
After that simple type $make unified and the output will be located at the same folder as project resides
Add the ZBar.dll to your project's References list.
For Release builds, currently the native linker has to be explicitly configured to not strip the NSDictionary key constants. Add the following to the 'additional mtouch arguments' section of the iPhone Build project settings: --nosymbolstrip=ZBarReaderControllerResults
See here for details: http://stackoverflow.com/questions/15150412/