What do I need to to do to obtain a micro-SIM in Ulan Bator, Mongolia?
Specifically:
Will I need to present my passport?
Is there anything I should know about the telecommunications companies, for example, owned by the government?
Recommended places to purchase the SIM, specifically a place with good English speakers.
Any other information that would be helpful to a one time visitor who plans on using a smartphone for about a week?