On April 24, 2007, congressman and presidential candidate Dennis Kucinich introduced HR 333, calling for articles of impeachment to be sent to the US Senate against Vice President Cheney. The grounds for impeachment can be found here. You can sign this form to tell congress and your local newspaper that you support the resolution.

You can email your representatives from this page as well, telling them to support HR 333. I recommend contacting congress from both links for good measure.