I use Etisalat with my IOM SIMs all the time, and it works fine.
I believe Etisalat is 900 only (and WCDMA, but, that's irrelevant on the world SIMs), see here
http://www.gsmworld.com/roaming/gsminfo/cou_ae.shtml
Keep in mind, UAE has blocked Skype (and possibly other VoIP services), so, you will not be able to use it there (although you can have Skype forward to your UM card, if you wish, but, do it before you go!)
The UAE actually block many sites, including any sites with any nudity, foul language, or even dating, like jdate, match, etc ... when I tried Islamic dating sites, just to see, the dating ones were blocked, but, the ones that look specifically for a Muslim wife worked!
It's actually kind of nice, as they inform you that it these sites are "inconsistent with the cultural, political religious, and moral values of the UAE"
See here
http://www.pbase.com/bengalboy/image/69955145.jpg