I have always wanted Tibet to be free, ever since I read Heinrich Harrer's account of his visit there (Seven years in Tibet).
If you want to show solidarity for Tibet, on 8th August, on the day of the opening ceremony of the Olympics, place a candle in your window for Tibet. If millions of people do this, it might get onto the news. It's also an act of global consciousness.
Other things you can do: sign the Avaaz petition; donate to one of the organisations linked below; write to your MP.