OS X icons size

Question

What size should an application icon and menu bar icon for OS X be?

I can deal with small resolution displays but what about Retina - does an icon displayed on the men

Answer 1

http://developer.apple.com/library/mac/#documentation/userexperience/conceptual/applehiguidelines/Intro/Intro.html#//apple_ref/doc/uid/TP30000894-TP6

And: http://developer.apple.com/library/mac/#documentation/userexperience/conceptual/applehiguidelines/IconsImages/IconsImages.html