Newspapers vary. Our local paper takes letter far in excess of 600 words. Many of the papers I saw today were 200-450 words. Because of the way the letter is written, it is easy to take out a couple paragraphs to accomplish any restriction on length.
Whether someone uses my letter or their own, we should all do something. That is the point.
You're right--people need to do something. But copying and e-mailing someone else's letter isn't doing anything. Yes, you might have to take a half hour or an hour to put together a short, thoughtful letter. You might have to do some research on the internet so you can back up your arguments. You might need to take a few minutes and think about the voter you're trying to convince to vote for Bush, rather than trying to convince the voter who is already voting for Bush. But it's worth the time. Write letters, post blogs, talk to people, but in your own voice. Being genuine will convince more undecideds.
Unless they're leaning towards Kerry. Then you need to scare the heck out of them.