Came across this on the Catholic Online Saints FAQ while searching for info for the St Stephens Day thread. Hope it helps to answer your questions, Paul.

Is keeping statues or pictures of saints idolatry?

Look at the pictures of your loved ones in your wallet or around your home or office. Why do you keep these particular pictures? You might answer that you carry those pictures to remind you of people you love, to help you feel that they're close to you when you're not together, or to share with people you meet. But you probably didn't say you worshipped them. Those are some of the same reasons we have statues and pictures of saints. Seeing a statue of Saint Therese of Lisieux who lost her mother when she was a child might make us feel less alone when we are grieving. A picture of Saint Francis of Assisi might remind us of how much he loved God's creation and make us more aware of our environment. (top of the page)

Do Catholics pray TO saints?

We pray with saints, not to them. Have you ever asked anyone to pray for you when you were having a hard time? Why did you choose to ask that person?

You may have chosen someone you could trust, or someone who understood your problem, or someone who was close to God. Those are all reasons we ask saints to pray for us in times of trouble.

Since saints led holy lives and are close to God in heaven, we feel that their prayers are particularly effective. Often we ask particular saints to pray for us if we feel they have a particular interest in our problem. For example, many people ask Saint Monica to pray for them if they have trouble with unanswered prayers, because Monica prayed for twenty years for her son to be converted. Finally her prayers were answered in a way she never dreamed of -- her son, Augustine, became a canonized saint and a Doctor of the Church.