Can you share marker tracking source for iphone xcode please
OpenCV is a great library for feature detection that a lot of AR apps or toolkits use -- http://opencv.willowgarage.com/documentation/feature_detection.html -- feature tracking is another way of saying marker detection, so if that's explicitly what you want, this might be your best best.
http://www.morethantechnical.com/2009/07/01/augmented-reality-on-the-iphone-using-nyartoolkit-w-code/ -- is the ported version of nyartoolkit for the iphone. google/bing is a friend.
http://www.artoolworks.com/ARToolKit_iPhone.html is another full AR toolkit, may be worth checking out.
Hello, I've found a blog describing to use NyARToolkit on iPhone: http://www.morethantechnical.com/2009/07/01/augmented-reality-on-the-iphone-using-nyartoolkit-w-code/
It has marker tracking features. You can make markers with ARToolkit's mk_patt tool.