here is the petition/letter, with intro. from http://www.savearcticrefuge.org/
Below this I will paste in the EARTH DAY letters (one version to be sent to senators who voted pro-drilling and another for the more conservation-minded senators)

"March 16th the Senate voted by a razor-thin margin to open the Arctic National Wildlife Refuge to oil drilling by sneaking a measure into the budget bill. But the fight to protect the Refuge is not over. Send your Senators and Representatives a message now, telling them to vote against any FINAL budget measure that would allow oil drilling in the Arctic Refuge."

"Dear Senator/Representative,

"As your constituent, I strongly urge you to vote against ANY budget measure that would allow oil drilling in the Arctic National Wildlife Refuge. The inclusion of any such measure in the budget is an unacceptable sneak attack on our precious wildlife.

"Drilling in the Arctic Refuge is not a path to energy independence or lower prices at the pump. The United States Geological Survey estimates that the Refuge has less than a single year's supply of oil that would not reach the market for at least 10 years. Meanwhile, the harm to wildlife and to our greatest wildlife refuge would be irreparable. We need to save national treasures like the Arctic National Wildlife Refuge for future generations.

Sincerely, "

Below are the letters from www.earthdayvirtualmarch.org/
If you are from the US and you submit your name and postcode, the organisation will mail your state senators on your behalf. There is also a map on the page showing from where people are virtually marching [making and using computers uses fuel - we are all "co-opted", but I suppose a virtual march is less resource-exhausting than when people physically travel to the site]and has facilities for "marchers" to invite their friends and acquaintances.

Letter 1
"Dear Senator,

"As a constituent I wanted to express my thanks for your voting to protect the Arctic National Wildlife Refuge. While Im disappointed in the outcome of the first vote, I urge you to continue your efforts to block final Congressional passage of any budget bill that includes drilling in the Arctic Refuge.

"On this Earthday we should consider what strong actions should be taken to save wildlife, its habitat and the environment we share for future generations of Americans. Not only should we continue to protect our Clean Air, Clean Water, and Endangered Species Acts, but Congress should end this constant battle over the Arctic National Wildlife Refuge. Please set aside the Arctic National Wildlife Refuge from drilling once and for all through the Eisenhower-Udall Arctic Wilderness Protection Act (S.261 and H.R. 567).

"Sincerely,
Your Name "

Letter 2
"Dear Senator,

"As a constituent I wanted to express my strong disappointment over your vote to allow oil drilling in the Arctic National Wildlife Refuge. My hope is that you will reconsider your vote the next time this comes before the Senate.

"On this Earthday we should consider what strong actions should be taken to save wildlife, its habitat and the environment we share for future generations of Americans. Not only should we continue to protect our Clean Air, Clean Water, and Endangered Species Acts, but Congress should end this constant battle over the Arctic National Wildlife Refuge. Please set aside the Arctic National Wildlife Refuge from drilling once and for all through the Eisenhower-Udall Arctic Wilderness Protection Act (S.261 and H.R. 567)."