I sent a snail mail letter out today. Snail mail letters make more of an impact than email or e-petitions, so I encourage anyone who has an interest in the game to do likewise.
I recommend strongly, however, that you word your letter in a somewhat professional fashion. That means using proper grammer, spellchecking, punctuation, full words (never use 'u' for 'you', etc) and an appropriate letter format, either block or indent style. Even if you wish to keep the tone of your letter negative (as I did), avoid profanity.
You can see one of the later revisions of the letter that I set in the "Sam & Max 2 cancelled" discussion on this forum.
You can find examples of the proper formatting for business letters at
Be sure to include your address at the top (as indicated) and your full name at the bottom.
You can find examples of the proper formatting for envelopes at