You are not given a sim card, but it's easy enough to get one.
There are either plans or prepaid accounts for both operators here (Etisalat & Du)
It costs about 75dh for a SIM card. You can get one with a copy of your passport and temporary visa.
The only exception I know of was in Nad Al Sheba when the buildings were new and there were no landlines yet installed the company provided a mobile phone that crew could be cntacted on.
BBM works, after RIM worked out a deal with the government. Download the video calling one before you come. If you want a VPN, get it before you leave.
Most phone models can be purchased either bundled with a plan (by operators) or unlocked and useable on any network.
There are places you can get phones unlocked for a fee. If you can pass on your phone to someone else to take on the plan and buy one here, great. If not, it might depend on your provider if you can unlock it or not.
Electrical outlets are either UK 3 plug or Euro 2 plug. Adaptors are easily available here.
For more info try etisalat.ae it has all the info on the plans and costs etc.
I use data on a prepaid sim card separate to my 'regular' phone which is just a basic Nokia. I use 20dhs a month on the prepaid one and I've never run it out before the expiry date of one month. That's used for BookFace, emails etc
Ipads are similar, can get data plans or prepaid for them too.