iPhone4 As far as I know only one company out there handles the iphone4 and thats etisalat mobile. You can go on their website to look at their packages
iPhone
Also, you just have to get your phone unlocked so it can be used but if I read correctly there are places in Dubai that can unlock your phone for as low as 50AED.
Medicals There's a list of the medical exams they asked for in this thread. Just type "medicals" in the search option of this thread or you can go to the thread created before this one (
here). I would advice you to start now because I've heard/read stories on here with people waiting up to 1.5 weeks to get an appointment not even including the wait for results especially for the PAP smear and you have only 2 weeks to complete your medical exams.
Also, when you receive your GC you may not have access to the portal right away. Sometimes it can take up to 4-5 days before you gain access to it. So, don't worry if you cant go on it immediately.