It is remarkably easy to write a Senator.
I sent this to Maryland's veteran Senator a few moments ago...it only took a few minutes.

Dear Senator Mikulski,
I am writing to urge you to question Alberto Gonzales's record on the Geneva conventions, the treatment of prisoners, and the use of torture. The policies he has affirmed and advocated have been linked to human rights abuses in Abu Ghraib and elsewhere that I, as a proud American, cannot help feeling personally responsible for and ashamed of. Mr. Gonzales's policies have caused enormous damage to the United State's honor, reputation, and ability to act as a trusted and respected partner and leader in the world. Today's lead editorial in the washingtonpost puts this case far better than I can: http://www.washingtonpost.com/wp-dyn/articles/A3187-2004Nov21.html
I trust that you will represent those values which make our country great. I trust you will represent me and the American people and speak out on this issue, urging your colleagues to do so as well.
Thank you for all your work and service on my behalf.
Sincerely,
Ari Johnson