When I came here it was really easy to get my visa. When you check in at customs just tell them that you want a tourist visa. They will ask you where you are going to stay and then you have to pay 100 riyal. Be sure to have a credit card ready b/c you can't pay in cash. After that they will stamp your passport and you are good to stay there for a month. If you want to stay longer than that you come back at the end of you month (to the airport) and go to the Visa building and tell them you want to renew it. YOu will have to get some papers signed and then go and buy a "ticket" from Qatar Airways (300 riyal) and then go back to the visa building. It take like 20 minutes, but you will be good for another month.

Ok, hope that helped ya.