There are two ways to get a Vietnamese visa - find a Vietnamese Embassy, or pay a bit more and get a travel agency to do the work for you. My previous two visas (Myanmar, Laos) were through travel agencies and pretty much hassle-free. This time I decided to do it myself: I'm in Vientiane, the capital of Laos, and it's easy to walk to the embassy. As it turned out, the application was fairly simple and the only things I had to worry about was how long a visa I wanted. The default is one month, which costs $50US (expensive: Myanmar was around $25, Laos around $30, each for a month). I went for three months (the only other option) as I'm expecting to be there six to eight weeks. This cost $80US, and processing takes three working days. I got to keep my passport, which kind of surprised me. One irritating feature of Vietnamese visas is that they start and end on specific dates, whereas most countries allow you to enter any time in the next three months and then the visa is valid for one or three months after the date of entry. My dates seem to be okay, so it's not a major problem.
I also got a Laos visa extension as I'm expecting to come up a few days short for the things I want to do (the default here is a two week visa, but I paid a bit more and got a one month visa). Vientiane is the only place you can get visa extensions, so even though my visa doesn't run out for a couple weeks, I extended it now. It costs $2US per day, and I asked for five days. Again, fairly straight-forward at the Immigration Office, but when I tried to pay in kip, the government office insisted on U.S. dollars! The government has issues with their own currency?
Here's what a Myanmar Visa looks like, along with the enormous stamp for an extension of stay: