Muang Xay (Oudomxay, Udomxai etc) is the capital of the multiethnic province of Oudomxay Province, located in the Nam Ko River Basin and surrounded by scenic mountains. It's the largest city in Northern Laos and, if you're travelling by land, you'll probably end up here at some point.
The town is formed by small villages at an important intersection between China and Vietnam, and the city has a unique multicultural atmosphere.
A free city map can be obtained in the bus station, with basic information and "things to do".
An online version you can get on the website of the Provincial Tourism Department.
Lao Airlines has three flights a week to/from Vientiane (1 hr, full fare US$98). The local ticket reseller is located in Litthavixay Guesthouse in the town center on the main street.
Buses from/to Luang Namtha cost 28,000 kip takes up to 3.5 hours. Departures from Muang Xay are at 08:30, 11:30 and 15:00.
Buses from/to Luang Prabang leave once a day and take about 5 hours.
Further daily buses come from/go to Vientiane, Phongsali, Pak Beng, Muang Khua, and Bokeo. Buses to China can also be reached.
The local Provincial Tourist Office (in Oudomxay City, or Muang Xay) has been offering since November 2006 some very nice hiking including nightstays in khamu family houses (not guest houses, as in other more touristy hike places, which makes the experience very special and intimate). Although not as colorful as other ethnic groups of Laos, the khamu people are very nice and happy to have foreigners visiting their villages.
There are three banks and one post office offering change for cash and travellers' cheques, BCEL , about 1 km north of the bus station change travellers for 3% commission (minimum of US$3). It might be worth checking Lao Development Bank (which might offer a better value).
BCEL provides an ATM, accepting international cards (BCEL charges 20,000Kip, be aware of charges of your own bank).
There is a market located opposite the Tourism Office where you can buy stuff mostly from China and Thailand. Get your daily necessity stuff at the market and please do some bargain when you buying from them.
Quite a few restaurant practice dual pricing, often with ridiculously high "foreigner" prices. Check the menu first and just walk away.
On the Tourism Office's town map all restaurants are shown.
There are a number of decent guesthouses in town. Basic rooms with showers and hot water should cost around 40,000 kip. General room prices in the town center including TV are around 60,000-70,000 Kip.
The town has two laundromats (one just a few meters south of the bus station) which charge per item which makes the service very expensive.
There are two Internet shops in the city (one located in the bus station), both charging 400 kip/minute.