Sras Srang lake at dawn
A 30 day tourist visa is available upon arrival for $30 USD at the time of writing. You will need one passport photo.
The US dollar is Cambodia's most common currency. The local currency is Reil and it is used for smaller dollar amounts as US coins are not available. There are a number of ATM's in Cambodia.
Throughout Cambodia the voltage is 220/230 AC. It is advisable for travellers to bring an adaptor. 
Cambodia is hot and humid with the wet season from May to October bringing 75% of Cambodian's annual rainfall.  The average temperature is from 25 to 35 degrees. 
Some temples require your shoulders and knees to be covered. Travellers are advised to wear appropriate clothing. Scarves are not always accepted as appropriate to cover shoulders in places of worship.