Element Size (in pixels)
Window (including status bar) 320 x 480px
Status Bar
(How to hide the status bar)
20 px
View inside window 
(visible status bar)
320 x 460
Navigation Bar 44 px
Nav Bar Image /
Toolbar Image
up to 20 x 20 px (transparent PNG)
Tab Bar 49 px
Tab Bar Icon up to 30 x 30 px (transparent PNGs)
Text Field 31 px
Height of a view