The most popular club in Wieng Chan (Vientiane) now is Kok. Any tuk-tuk driver will know where it is. It is a five to ten minutes ride from the fountain area.
Also, the BBQ place next to the fountain is all packed with farangs, both expatriates and back packers, and consequently attracts the young male (and female) crowd. Just sit by the bar and relax, and the boys will come to you.
And of course,
www.face-pic.com is a good bet.
Face-pic also has a lot of Myanmar guys, but my contacts never turned up at appointments. That is my experience.
Good luck.