The SBB have some special offers on travel passes during Euro 2008,
see this page for details. Here's a brief summary:
A one-month half-fare card (valid June 1st-30th) is 39 CHF if bought by May 31st, 59 CHF from June 1st. This would normally cost 99 CHF. This allows you to pay half price on nearly all trains, coaches, and boats in the Swiss travel system, and half fare on the Austrian rail network.
A one-month general travel pass (general abonnement, GA or AG, valid June 1st-30th) is 299 CHF (459 for 1st class) if bought by May 31st, 399 CHF from June 1st (599 for 1st class). This would normally cost 578 CHF (867 for 1st class). This gives you unlimited travel on nearly all trains, coaches, and boats in the Swiss travel system (you'll still pay half price on most mountain railways), and pay half fare on the Austrian rail network.
If you have a ticket to one of the matches (lucky you!) then you get a free trip to and from the venue from your home address, hotel, or airport on the day of the match up to 12 noon the next day,
see here for full info.