This website might be worth a look Embassy Website
There is also a section on here to check re medication, as already mentioned codeine is banned here, so make sure if you do have to bring anything over you have a doctor's note.
As for clothing, as already said, what you wear on the beach stays on the beach, once off its polite to cover up a bit. If you are in the malls, the general rule is shoulders and knees covered. You will see plenty people here that don't cover up and there is no actual law, just a dress code. Obviously there are decency laws, so wearing your bikini in the mall is a no-no!
Alcohol is expensive, but plenty of bars in hotels to choose from, so no shortage of it.
Ramadan starts in July next year, so you won't be here then if you are thinking of early 2013. The weather can be a bit iffy in January/February, and can get a bit windy and even rainy, although if you are coming from the UK, it will still feel lovely and hot by midday, although morning can be a bit cool (14/15 degrees at coldest).
Plenty of places to visit, would recommend a Desert Safari. Just use Google to search for places to visit. Also, would recommend getting an Entertainer Book, as these pay for themselves in no time, they are basically a voucher book, so you get two for one on everything (including Desert Safaris), so if there is more than just you, well worth buying. The water parks are great here too and vouchers are in the Entertainer book for these.