Cambodian Currency

US dollars are as commonly used as the Cambodian Riel and even Thai Baht is acceptable in many places. Most hotels and many restaurants and shops set their prices in dollars. Small transactions are usually done in Riel. You Must carry some Riel change for motorcycle taxis, snacks and other small purchases.
Riel notes come in 50, 100, 200, 500, 1000, 5000, 10,000, 50,000 and 100,000 denominations, but the distinctive red 500 Riel note is the most commonly used.

Credit cards and travelers checks are not common but are catching on. US dollar travelers checks are much more easily encashed than any other kind. 

Money changers cluster around the markets. When accepting money, inspect the bills. Marred Riel is acceptable tender, but the smallest tear in a large US note renders it worthless.

There are banks in all of the larger provincial capitals, including Phnom Penh, Siem Reap, Sihanoukville, Battambang. Banks can change money, make telegraphic transfers and some banks can cash travelers checks and accept Visa cards.

1 Cambodian Riel = 0.0002519 US Dollar
1 US Dollar (USD) = 3,970.50 Cambodian Riel (KHR)

Clothing

Under the warm Cambodian sun, productivity relies heavily on the suitability of one's dress. Since little is accomplished in blisteringly hot clothes, Khmer people for generations have tied kromas around their waists to work and play in cool comfort. The Khmer scarf, woven from cotton or silk, has been a fashion staple since ancient times. While some claim the thin cloth, wrapped around one's head or neck, is used primarily to wipe the sweat from a hot face, others say wearing a kroma is as 'Khmer' as wearing a necktie is American. Buddhist Institute's Mores and Tradition Department in Phnom Penh explains that the kroma has had a home in Cambodia since the first century reign of Preah Bath Hun Tean. It is not clear when exactly the kroma hit the streets, but it has been a symbol of the Khmer kingdom and its people ever since.

 
Codes of Conduct

When visiting temples or pagodas, including those of Angkor Wat, shorts and T-shirts are acceptable. Shoes are generally removed at the entrance to pagodas. For visits to the Silver Pagoda, which is on the Royal Palace grounds, visitors are asked to dress more formally. Gentlemen are required to wear long trousers and ladies should wear long pants or long skirts.

Misc:

Standard film, (such as Kodak, FUJI or Konica 100 ), slide and digital camera memory are widely available. Photos are inexpensive to process in the country. Any specialized photo equipment should be brought along. Photography in airports, railway stations and nearby all military installations is forbidden and discretion should be used when photographing people, particularly monks.

HEALTH REQUIREMENTS

Although no vaccinations are officially required for entry into Cambodia, they are highly encouraged. Visitors are advised to check with their physicians or a travel immunization clinic regarding protection against malaria, typhoid, tetanus, hepatitis A and B. Any essential medications should be brought along as there is no guarantee that they will be available in Cambodia

Drink lots of water. Never drink tap water, purified bottled water is available everywhere.

Use an insect repellent against mosquitoes. It is the only way to be sure of protection against mosquitoborne diseases. Since Cambodia has a tropical climate that is hot and humid, casual and light-weight clothing is best. Clothing made from natural fibers is the best option. A jacket might be needed on cool winter evenings or in hotels and restaurants with excessive air-conditioning. Hats and high-factor sun block is advisable against the hot sun when sightseeing.