I've been in Germany on christmas and almost every city has a Chrismas Market. Are there Christmas markets in Switzerland? Which are the most famous/interestings? When do they end?
This page list all the big Christmas markets in Switzerland. I can really recommend those two that are in the main stations of Lucerne and Zurich. It sounds weird but they are really nice. As a plus next to the Christmas market in Zurich's main station, there are a lot of open air bars in the courtyard of the Landesmuseum where you can get Glühwein and Raclette, typical food and drink during Christmas in Switzerland. As lejohn already mentioned, also the Christmas market in the Niederdörfli is worth a visit.
Here you see a picture of the Christmas market in Zurich's main station. The huge Christmas tree is decorated with Swarovski crystals.
And here is a picture of the Landesmuseum's courtyard where you can get Raclette and Glühwein. It is also possible to do some ice skating there:
There are a couple of Christmas markets in Switzerland, just pick one next to the place you are staying.
A nice market is the one in the old town of Zürich. It is located along Hirschenplatz, Niederdorfstrasse and Rosenhof. In 2011, it takes place from the 8th to the 23rd of December. Its opening hours are from Monday to Friday 11am - 8pm and on Saturday and Sunday from 11am to 6pm.
As I remember, in Geneva at least, there are open air markets on a weekly basis. (At least in the late 1990s, when I was there.) They do not "end," therefore, and there would be something for Christmas.
Another place in Swiss French part is Montreux, it is probably the biggest and longest running Christmas market in the French-speaking region.
Near Geneva, there is one in Carouge (the town is next to Geneva).
Apparently the biggest Christmas market in Switzerland is the one of Basel
This site is resuming all markets in Switzerland (and other countries).