I just went to Dubai one month before...
if have Qatar Visa...it's more easy
if you r in visiting visa here also no problem you better take Dubai visa from the following agency I hope which is better and good :

Cozmo Travel WLL
15-Doha Aljadeeda, B-Ring road,
P.O.Box 35380, Doha, Qatar
Tel: + 974 4407 3444
Fax: + 974 4427 0013
[email protected]

Enjoy,,,,