Roughly 4km north of each city's center, the Second Thai-Lao Friendship Bridge (http://en.wikipedia.org/w...) connects Mukdahan with the Lao city of Savannakhet on the opposite side of the Mekong river. There is a regular bus connection between the cities; a one-way ticket costs 100 Baht December 2009. While there is no formal bus stop at either end of the bridge, passengers need to disembark for the border formalities on both sides; hence in practice it's possible to buy a ticket and board the bus on the border if you've arrived there by other means.
There is a car park on the Mukdahan side of the bridge, one night costs 100 Baht. With the correct paperwork it's also possible to drive your car over to Laos. There are no pedestrian lanes on the bridge.
Visa-on-arrival is available at the border post for those nationalities that require one see the article on Laos for more details. Additionally, the Lao border officials charge an "entry fee" 40-170 Baht, "exit fee" 40 Baht and after 4:00 PM, an "overtime fee" 40 Baht for stamping one's passport.
