On Monday, 13 September 2010, WRS aired a very informative segment called "It's the Law," related to employment contracts in Switzerland. In short, get everything in writing.
Here is the link: http://worldradio.ch/wrs/programmes/swisslaw/its-the-law-swiss-law-on-employment-contract.shtml?20788
It's the Law: Employment contracts
Job contracts come in all shapes and sizes in Switzerland. Lawyer Stephanie Fuld spells out what exactly constitutes an employment contract under Swiss Law: