Maqu is a county-level town in Gannan Tibetan Autonomous Prefecture in the southern part of Gansu Province.
Daily buses from Xiahe, Hezuo, Luqu, Langmusi (mini-buses), Lanzhou, Linxia... schedules vary, tickets can be purchased just prior to departure.
The town itself sits about a kilometer north of the Yellow River, which along with the vast grasslands, is the town's main attraction. To get anywhere outside of the town and the nearby river area, you will need to hire a private car/taxi or try to take one of the daily buses heading off to south in the direction of the more remote villages of Maqu County.
Numerous grasslands, the Yellow River, dark-skinned Tibetan nomads... pretty much anywhere you go there will be something interesting. If nothing else, you will be in one of the most remote regions in China beneath a deep-blue sky in the midst of never-ending grasslands...
There aren't too many shops catering to tourists, but you will probably see lots of Tibetan cowboy hats available. The sun is hot & bright @ 3500+ meters (12,000+ ft)!!!
Local Muslim noodle shops & Sichuan Chinese restaurants abound... and if you are looking for "local Tibetan" food, this is about it... the locals are by far the main customers at these restaurants!
You'll enjoy your visit more if you don't drink alchohol, especially at this altitude.
A couple larger hotels (doubles ¥100-200) are around, as well as many cheaper Chinese-style hostels (dorms, doubles from ¥20/person)
For any other questions, you can contact Eugene @ http://www.snowymtncafe.com in Xiahe. He knows the region better than most...When I just tried to open the Snowy Mtn Cafe website (July 16, 2009), it was being blocked in China. I managed to gain access using the following proxy: 
You get out the same way you got in... the same bus routes depart Maqu as those which arrive...