There is a great article by Larry Keefauver over at Charisma regarding faith healing.
Here is a summary of the myths..
Myth #1 is that God always heals now at the initiative of our faith.
Myth #2 is that if you stand fast in faith, you will be physically healed in time and space.
Myth #3 is that if you just confess your healing, you will be healed right now.
The faith healers on television and elswhere have done a great disservice to the world with their twisted view of biblical healing.