Yes, usually 3 days. Submit your application on day 1, they make a photocopy of your passport, hand your passport back to you (which is useful) and on day 3 you bring back your passport and wait for around half an hour at which time your visa is stamped into your passport. If you are a dual national you are allowed to get your Myanmar visa stamped into another passport that isn't the same one as the one used to enter China, but you would need to show your Chinese visa too in that case.

Also, despite the road from Huay Xai to Nam Tha being a joint Thai/Chinese effort and in pretty good condition (I drove between the two towns in 2h45m in my Ford Ranger, Lao registered) whereas years ago it was an 8hour dusty ride by songthaew (pickup with benches at the back), the road strangely does NOT feature any overtaking/passing lanes. No idea why such a twisting and winding road doesn't have such important passing lanes built such that you can safely overtake a slow crawling bus or truck. The roads on the Thai side are a million miles ahead and actually feature regular passing lanes, that is, if they aren't already 4 lanes or more as there are fewer and fewer 2 lane roads left in Thailand.

The Thai/Lao border closes at 2200 (10pm) but for some bizarre reason (possibly due to it's isolation) the China/Lao border closes much earlier, around 5pm Lao time as another poster mentioned.

@Alien,

@Alex: maybe I'm wrong, but I think the entire road to Huayxai was built by Chinese companies. In fact the road south from the border to Luang Prabang was originally (? I don't know what was there before) built by the Chinese in the 60s to aid the Pathet Lao & Viet Minh in their war effort (the north of Laos had not been under the control of the central government, or the Americans, for years. It's winding and indeed rather tiring - the road to Huay Xai is much better.

I believe the road from Luang Nam Tha to Huay Xai was a joint effort by Thai and Chinese companies, not merely Chinese ones. Also the 4th Mekong Bridge was a joint Thai/Chinese/Lao effort.

ATM machines are available - although you can't enter there for now coming from China there is even one in Muse, which I have used and yes, it worked!

In most larger cities and towns there should be a few ATMs but they aren't numerous yet. 5000 Kyat fee is applied to all withdrawals and the max withdrawal per time is 300,000 Kyat, which is a reasonable amount.

Overland routes to/from Thailand are OK I have been overland from Thailand to Myanmar 3 times. And no, I'm not talking about day trips or limited distance trips, I'm talking about Bangkok to Yangon overland. However, the Ruili-Muse crossing, which supposedly will open sometime this year, has not yet opened without a permit. Muse however is accessible from within Myanmar coming from Mandalay. I was there last year.