I believe I have to get a laos visa from penom penh befor crossing the border into laos from cambodia. does anyone know where the laos embassy is and how much tourist visas cost? thanks

On 9th May last year I took a bus from Stung Tren in Cambodia to Paksan in Laos. The border crossing was a hut on the side of the road, but they happily took my 1000Baht and gave me a proper visa for Laos for 30 days. You can visit the Lao embassy in Pnom phen - all the tuk-tuk drivers know were it is

One word of general caution - make sure you travel with lots of spare passport/visa sized photos, and some photocopies of your passport main page. These are invariably needed when asking for a visa. Avoid hitting border crossings at times other than Monday to Friday 09:00 to 17:00 or you might be charged "overtime" - which seems to be a very moveable thing and has many ways to be calculated.

Good luck on your travels.