You have to be over the age of 17 :) and have to take practical driving lessons. The number of lessons depend on whether you already have a motorbike license in another country or whether you are a beginner. If you are a beginner, you have to take about 30 classes. You can take these from Emirates Driving Institute at a cost of about AED 3000. EDI have a branch at Mall of the Emirates where you can get more information and also sign up for driving classes.
ETA: I'm sure Belhasa and other driving schools also offer classes, I just mentioned EDI because thats where my brother applied for his.
<em>edited by em2san on 28/03/2011</em>