In early October 2006, the rule requiring an NOC (No Objection Certificate or letter) from your sponsor was reinstated. You need this before you can start taking driving lessons.
After the driving school has decided you're a good enough driver (that may depend more on how much cash they've received as lesson fees, than on your actual driving skills), they'll make an appointment for you to do a driving test with the Dubai Traffic Department.
You could try making an appointment directly with the Dubai Traffic Department but it would make sense to do a couple of lessons first. Not because you don't know how to drive (there are many licenced drivers in Dubai who obviously fit that category) but because the driving school will, in theory, prepare you for the driving test (as opposed to teaching you how to drive safely).
The Dubai driving test involves answering some multi-choice questions on theory and then a short drive around the block. A surprise for many will be that the driving test car will contain several applicants at once, and you take turns. The tester may be obnoxious and/or inconsistent but remain calm and polite. If you get failed the first time, you might get the same person next time round. Note also that you do the test in a different car than what you had driving lessons in, so the brakes, transmission, controls will be different. Try and practice short drives in different cars, especially if you're being tested in a manual car . The clutch always seems to be difficult for beginners to get used to.
When you do the test, make it obvious that you are adjusting seat and mirrors before starting, checking mirrors and over your shoulder before changing lanes, checking the rear view mirror, etc (same anywhere really).
The driving test results are notoriously random - anyone who's attempted it is bound to have a story. Most people take more than one try before succeding. There was supposedly a wait of six days before you could do a re-test. The RTA changed this to one month late in 2006. It may be reduced according to comments in Mar 2007 from the RTA.Check also if there is an extra fee for urgent applications to speed it up.
Although it's true that many people complain that it's impossible to pass the driving test in Dubai, you'll find it interesting while doing the test that some of your fellow examinees obviously have no idea how to drive in Dubai and should not be let anywhere near a car. Ever. Unless tied up, enclosed in a large bag and deposited in the trunk. You may have less sympathy for those who tell you stories of making their 20th attempt at getting a driving licence in Dubai after being in the car with one of them while they do their driving test in Dubai.
If you pass the driving test, then you'll get your Dubai driving license there and then - you'll need all the documentation listed in the previous section though.