thanks to tomongolia for information!

Ps all prices 2011

Buses go from Ulaanbaatar to all Aimag (province) centers. From the Aimag center you wait with others for a van to fill up going to a Sum (district) center. If you attempt to go to a tourist attraction that is not on the public transport routs, you will find jeeps or vans ready to be hired to take you to a specific location. Any private car can act as a taxi.

Destinations in Cyrillic
To identify the proper van have the destination name in Cyrillic letters with you. The vans display a board with the destination on the windshield.
Example: for a van going to "Terelj"  look for a sign saying  Тэрэлж

Vehicle
Public transportation vehicles include buses, minibuses,  vans and cars.
Buses leave at a set time, minibuses and vans leave when they are full.

Bus Stations
There are four main departure stations in Ulaanbaatar (Ulan Bator).

1. Dragon (Songino Khairkhan)- buses going north and west.
2. Teevriin Tovchoo (near Idre's guest house)- vans going north.
3. Bayanzurkh- buses going south and east.
4. Narantuul (Black Market) - vans going west and north.

Tickets
For long distance buses you have to purchase the ticket the night before departure.

Cost
The fare to Olgii is 63,000 Togrog which is 1,700 km to the west.
For comparison - locals pay at least 400 Tugrug per Km to hire a jeep  and driver, not including petrol cost. To hire a jeep to Olgii would cost 680,000 Tugrug. This is more than 10 times the cost of a bus ticket. (2011)

Travel time
It takes a 18 hours to get to the Gobi town Dalanzadgad, and 34 hours to get to Khoved in the west. The roads to most location are unpaved bumpy dirt roads.
River crossing like on the way to Moron is on a wooden barge.
The vehicles go non stop, with short breaks on the way.

Bus Atmosphere
Vehicles are packed full, with boxes of merchandise in between.

Featured Destinations
There are many routs, here is a sample of a few.

North (Khovsgol lake)

To go to Khovsgol lake take the bus to Moron.
Distance: 684 Km.
Cost: 24,500 Tugrug.
Departure Station: Dragon.
Departure Days: every day.
Departure Time: 15:00
Travel Duration: 20h to Moron + 3h Moron to Khatgal
In Moron you wait with others for a van to fill up-
going to Khatgal, the village on the southern shore of Khovsgol lake.

South (Gobi desert)

To go to the Gobi take the bus to Dalanzadgad
Distance: 575 Km.
Cost: 20,500 Tugurug.
Departure Days: everyday.
Departure Time: 8:00AM.
Tickets purchase: the evening before departure.
Travel Duration: 18h to Dalanzadgad
From Dalanzadgad hire a jeep to take you to the popular destinations.
Try and go with partners on the bus to share the cost of the jeep.

West (Altai Mountains)

To go to the west take the minibus to Olgii
Departure Days: Everyday
Departure Time: 15:00-20:00 leaves when full
Distance: 1,709 Km
Cost: 68,000 Tugrug
Departure Station: Dragon
Travel Duration: 45h-55h to Olgii
In Olgii hire a jeep to the mountains (i.e. to Tavan Bogd).

East (the steppe)

To go to the east take the bus to Choibalsan
Departure Days: every day
Time for bus: 8:00
Time for Minibus or Van: 9:00-10:00 leaves when full
Distance: 661 Km
Cost: 24,000 Tugrug
From Station: Bayanzurkh
Travel Duration: 12h