I'm searching foreign press center / association in Switzerland but couldn't find anything. I'm not sure if Switzerland has central office responsible for foreign journalists, media credentials... Any idea or tips will be helpful. Thanks...

I am sorry but
A) why should there be a "central office" ?
-- journalists simply can hire logdings and an office and start working
--- if from outside Europe they might need a Visa, but that is a matter of a Swiss embassy or consulate
B) and the business anyway would not be on a federal level but rather on the level of Cantons
C) there is a monthly journal named "Swiss News" available at news-shops, with lots of information, so that you might find something there

How about Reuters?

http://plazes.com/plazes/9283:reuters_geneva ?

The government has no power over foreign journalists (aside from being the residence permit authority like for all foreigners - but I haven't heard any reports that they're flexing that muscle). There's however an inglorious case on record where a federal council asked AFP to withdraw the accreditation of one of its journalists last year. (source: 1, 2)

Foreign journalists are organised in the APES (Association de la presse étrangère en Suisse et au Liechtenstein)

Thanks for the link...