If you mainly want calls take the Sunrise 1 CHF Day Flat. You can make as many calls to land-lines and Sunrise subscribers as you want. Combine that with a
Cheap International Calls | Localphone account, which has a Swiss land-line access number, and you can call worldwide for next to nothing. Sunrise also have an Internet plan, but I am not familiar with it. There are Sunrise stores all over including Zurich Airport. Recharging is available all over the place in stores [Migros] bankomats, stations etc. as well as online. You have to use the account at least once every 18 months. The Swiss Post Ofice is often the best place to buy phones with a SIM card and credit included. The bundle deals are usually very good. There is also a Post office in the airport. You will need a passport to get a SIM.