The URL for Apps and Artists in App Store

Examples:

http://itunes.com/XuanChen (for computer and iphone)
itms://itunes.com/XuanChen (for iphone only, only one redirection)
http://itunes.com/apps/XuanChen/MassageMap3D
itms://itunes.com/apps/XuanChen/MassageMap3D

More info:
http://developer.apple.com/library/ios/#qa/qa2008/qa1633.html