One bedroom is available in a nice apartment immediately. The apartment is bright, sunny, and spacious, and has a nice terrace with a view. The flat has 2 bedrooms with air-con, and is in BKK2, in walking distance to Wat Langka. There is a safe place to store bikes and motos, and also a washing machine, hot water, and internet. The apartment is nothing fancy, but cozy and pleasant and exceptionally good value for central Phnom Penh. The room rents for $125/month plus bills; total including internet, cleaner, & utilities is under $200.
You would be sharing with a friendly 30ish Canadian legal intern. The apartment also shares an entrance, terrace, spare room for guests/hanging laundry, and a few other features with the apartment downstairs, where another 30-something woman lives with her baby and affectionate pet cat (who freely roams both flats). On the nights when her nanny cooks dinner, a $3 contribution towards groceries will also get you a delicious home-cooked meal. And if you like to cook yourself, you have access to her bread machine and oven.
Email cm2530 [at] columbia [dot] edu to come have a look.