Can cops search your phone?

Things are going to become very interesting with our increasing dependence on technology to contain all of our personal information.

Not to go on a tangent, but how many phone numbers do you actually know without your cell to dial it for you?

Back on topic, to play devils advocate, what if you had an envelope stuffed with papers labeled ‘personal’ in your back pocket when you got arrested. Should the cops be able to look through that? What about your wallet? I take civil liberties very seriously, but its important to understand all sides of an argument as well.