As of May 2010, a visa is not required for United States citizens for stays less than one month when visiting UAE for business or tourism. For visits longer than one month, you must apply for a visa in person at your closest UAE embassy or consulate. To qualify for a visa as of May 2010, you should have a U.S. passport valid for at least six months, a round-trip airline ticket, proof of employment, a cover letter and a processing fee of $51.
In order to obtain a permit to work in the UAE you must already have an offer of employment. Not only will you need a work permit, or "labor card," but you also will need a residency visa. Prior to applying, you must submit to a medical examination to ensure you are healthy and do not carry any contagious disease. If you fail the medical exam, you will not be allowed to work in the UAE.
If you are immigrating to the UAE for work, your employer should apply for your residency visa. If you are also bringing family members who are not citizens of the UAE, they will need residency visas as well, and you will be able to sponsor them once you obtain your own residency visa. The residency visas are good for three years.
A visa is required for diplomats and governmental officials traveling to the UAE on official business, regardless of the length of stay. It is essential you possess a diplomatic or official passport to obtain a diplomatic visa. Your passport should be valid for at least three months and you will need to apply in person at the nearest UAE consulate or have someone apply in person on your behalf.