How to contact a pen pal for the first time and find a reliable snail mail program?

Unfortunately, I am not aware of any current reliable pen pal programs.

To initiate a pen pal friendship your letter should contain an introduction of yourself. Name, where you live, go to school, what the town/people is like (big/small, traditional, modern, country, etc), what you like, hobbies, food, hang outs, movies, etc. If you have an international pen pal it is fun to write about your culture and since Christmas is coming up you could talk about the Christmas preparations in your family. Including a picture is cool too or something from your town like a bumper sticker or something really inexpensive, keyring with a logo of your town, school, etc.

Then you stick your letter in an envelope and put a stamp on it and mail it. Make sure your postage is adequate for what is in the letter. More things in your envelope the more postage so you might have to take a trip to the post office to mail your letter and have the clerk there make sure there is enough postage on your letter.

Pen pal relationships can be a lot of fun and I had a couple when I was growing up. They fizzled out eventually as we grew up but I do wonder what became of my penpals.

You can try adding your profile to

http://www.palsnap.com/

It is an online penpal service with lots of pictures and people who want to meet