I couldn't be bothered to read what everyone else has written but it depends where you're from.

If you're European it's easy. She just comes in on a visit visa which lasts for around 30 days. I think you can get it extended if you want to or sometimes you just have to leave the country (to Dubai or Bahrain maybe) and then come back in on a new visa.

Yes,I suppose in reality it is against the law to be living with a female who is not your wife but everyone does it and no one really cares. Of course this would also depend on you having your own accomodation.

Don't listen to people who say she can't stay with you because it's illegal as I said in reality it is but no one cares!

Good Luck!