If you want travel at Angkor Wat..

SHIPS: Cambodia has only one sea port, Kompong Som. Tourists are not yet allowed to enter the country this way.

AIR: To Phnom Penh: Flights are available to Phnom Penh's Pochentong Airport from Bangkok, Hanoi, Saigon, Vientiane and Moscow (via Bombay). There is an airport tax of US$5 for international flights out of Phnom Penh. The staff at Pochentong Airport rarely speak English or French. Be prepared for problems and delays and make sure you arrive at the airport two or three hours before the flight.
Air Cambodia and Air Vietnam each operate a flight every week, one on Monday and the other on Thursday from Ho Chi Minh city in Vietnam. Air Vietnam flies to Phnom Penh from Hanoi every Wednesday. Lao Aviation has two flights from Vientiane to Phnom Penh on Wednesdays and Fridays. Aeroflot flies twice a month from Moscow to Phnom Penh.
From the airport: Private cars or small buses can be hired from the Ministry of Foreign Affairs or the Tourist Office. Generally, visitors are met by an official guide from one of these organizations on arrival at the airport.
To Angkor: Flights are available to the town of Siem Reap, situated a few miles from the Angkor temples, twice a week. They cost US$43 each way. Cambodian Airlines is on Tuoth Samouth Street. For information about tours to Angkor, contact the General Directorate of Tourism on Achar Mean Street in Phnom Penh.

BUSES: There is a bus service from Saigon to Phnom Penh via Moc Bai which takes between eight and 10 hours, with a wait of up to two hours for the ferry crossing of the Mekong at Neak Long. The bus leaves Saigon from Boi Xe 1A at 155, Nguyen Hue Blvd early each morning. Buses from Phnom Penh to Saigon depart daily at 6am from the corner of 211 St and Ok Nga Sou St (182 St). The border crossing is open from 6:30am to 6pm. At the moment, visitors are not allowed to travel by bus around Cambodia because of the security problems. They are allowed to take the bus from Saigon to Phnom Penh, but it is not encouraged by the officials. Buses around Phnom Penh can be taken by tourists.
CAR: You can drive to Cambodia from Laos along the National Route 7, from Vietnam via Moc Bai, and from Thailand. Phnom Penh is connected to Siem Reap by road, but be prepared for roads to be in extremely poor condition. A car and driver hired in Ho Chi Minh City or Phnom Penh costs about US$200 - 300 each way.
Around Phnom Penh: Cars can be hired in Phnom Penh. They cost US$25 per day and around US$150 / $165 outside the capital.
To Angkor: Visitors need a special permit to travel outside the capital and they are usually accompanied by a government guide.

TRAIN: There is no train service to Phnom Penh from outside Cambodia and no line which links Phnom Penh with Siem Reap. The existing railway line in Cambodia is extremely dangerous due to the tracks being mined regularly and is not used by foreign visitors.

HELICOPTER: An expensive but very exciting way to see Angkor is from a helicopter. Helicopters can be chartered for around US$6,000 for a round trip from Phnom Penh to Angkor.

BICYCLE: Bikes can be hired in Phnom Penh and Angkor and make for efficient easy transport.