iPhone
320 x 480
640 x 960

iPhone 5 – 640 x 1136. 326 ppi

iPad
768 x 1024

Toolbar and nav bar
Height – 44
Icon – 20

Tab bar
Height – 49
Icon – 30

AppStore – 512 x 512
iPhone App – 57 x 57, 114 x 114
iPad app – 72 x 72