Here it's pretty simple to buy tickets. You can almost always buy tickets outside the stadium or online.
The nearest top league club I think is Neuchatel Xamax. They also have a fancy new stadium.
The best atmospare would be in Basel or Berne. All tickets you'll be able to get online as well. in Xamax's case over www.ticketportal.ch
The problem is you've asked this question about 2 weeks too late. The games last weekend were the last before the winter break which goes until Febuary I believe.
If you are spontanious and are willing to travel. Basel play Fulham on Wednesday in the Uefa cup. I saw on their website they also play a friendly against Bayern Munich on the 12.1.10
Otherwise you'll have to wait till Feb.