An immediate question comes up whenever I read this passage: So does this mean that psychics and fortune tellers are really speaking with the dead? We can’t say that just because of this passage. God allowed it in this case to show Saul the cause of all his problems was his disobedience to God.
Many places in the Bible God spoke against mediums and fortune tellers. What makes Saul’s use of one even worse was the fact that he knew better. He had banned them from the kingdom according to the command of God. He did not follow his own rules (kind of says a lot about his lack of integrity.)
Do not put one ounce of trust in psychics, mediums, astrology or the like. These things are not from God. Simply trust in God above all things in all situations. He is the only one we can always trust.