SNB guarantees EUR/CHF at 1.20

Today 10:00 am the Swiss central bank SNB shocked markets with a press release stating the guarantee. The SMI is up 4%, EUR/CHF is of course 1.20 and the USD/CHF 0.848.
http://www.reuters.com/article/2011/09/06/swiss-snb-idUSL5E7K61FL20110906