iPhone UI Component height

Status bar: 20 pixels
http://developer.apple.com/iphone/library/documentation/UserExperience/Conceptual/MobileHIG/art/ui_statusbartypes.jpg

Nav bar: 44 pixels
http://developer.apple.com/iphone/library/documentation/UserExperience/Conceptual/MobileHIG/art/ui_navbarnonavigation.jpg

Tab bar: 49 pixels
http://developer.apple.com/iphone/library/documentation/UserExperience/Conceptual/MobileHIG/art/ui_selecteditemmodeswitcher.jpg

Toolbar: 44 pixels
http://developer.apple.com/iphone/library/documentation/UserExperience/Conceptual/MobileHIG/art/ui_taskstyletoolbar.jpg


from http://forums.ilounge.com/archive/index.php/t-224401.html