In App advertising - banner size

If you think you'll add in-app advertising, you should know which sizes are commonly used by the advertisers...
For this, you should check Table-3 in the page 3 of the MMA Mobile Advertising Guidelines

For people too lazy to load this (very interesting) PDF file :

X-Large : 300x50
Large : 216x36
Medium : 168x28
Small : 120x20
Tag lines : 10,12,18 or 24 characters width