I have participated in Letters to the Editor campaigns before, several kinds. In the normal ones, you get an e-mail from a group giving you facts on an issue, then asking you to write a letter to the editor about the issue. Often you can select which paper or papers you want the letter to go to.
I've also participated in campaigns where you write letters to the editor and they are submitted to various papers around the country by local people who sign their names to the letter you've written.
BUT I never participated in a campaign where you use FAKE and IMAGINARY personae to write the letters. The McCain campaign's use of this type of "fictional" letter to the editor is detailed in an article posted on Salon. (Thanks, Sara for sending it) The article is called "I ghost-wrote letters to the editor for the McCain campaign" and contains links to actual fictional letters to the editor.
Never a dull moment in this campaign!