Du will be launching on Sunday the 25th. Here is a link to their tariffs:
http://www.du.ae/en/pay-as-you-go/pay-as-you-go.html
They have a 3g data tariff that can be toggled on and off which might be helpful to some people. Unfortunately, their document list seems to suggest that you need to be a resident. I've e-mailed them for clarification on that point.
Stu