All travelers to Myanmar require a valid visa obtained in advance from a Myanmar Embassy. In the US, the Embassy is located in Washington DC: (http://www.mewashingtondc.com/home_en.php). Visitors are required to have a passport valid for at least six months and visa applications take about two weeks to process. Entry equirements and regulations are ever-changing, so check the latest from the government before booking a trip.
There are also a number of restrictions to enter Myanmar overland. As a general rule of thumb, it is not possible for non-Chinese nationals to from China, Laos, Thailand, India, or Bangladesh. There are some exceptions for groups, which will need to obtain special permission prior to travel. It is currently not possible to venture further than just the border town of Thailand.
Health and Safety
Myanmar in the past has had numerous bombings, uprisings and crack downs. Visitors should stay vigilant at all times and keep up-to-date on the political situation throughout their trip. It is best to avoid demonstrations and large gatherings. Travel to some of the remote states should be avoided, due to unrest. Many countries do not have diplomatic relationships with Myanmar so visitors shouldn't expect to rely on their embassy for help. Generally, travel in Myanmar is safe, with some petty crime in the cities.
Dengue and Malaria, which is transmitted from mosquito bites, is a concern throughout the year, but especially during the rainy season. Visitors should take care not to get bit and should bring plenty of bug spray. Tap water is not safe to drink and avoid ice in drinks. During the summer, remember to stay hydrated to avoid sun stroke and dehydration.
Good healthcare is only found at a few clinics that are up to international standards primarily aimed at foreigners such as the SOS Clinic, but treatments are still limited and expensive. For serious emergencies, visitors will need to be air-lifted to Bangkok or Singapore. Therefore, travel insurance is a must.