Never been there myself but one of my friends is working there. He said salary is dependent on your nationality i.e. higher if you have US/European nationality. Just a rumour, no data to confirm so take it with a pinch of salt.
I can tell you that is not only the case with programming jobs in Dubai, that is concerning everything. Employers there in start discriminate Indian, Pakistani, Philiphinese... people because most of them will work for a lower wage than a European. I have a friend working there in a hotel right now when she was switching jobs she told me her previous job got some guy from Philiphines for half the wage (she is European).