If someone you know has Internet access, and you'd like to drop them a note, there are many different ways you can find their address. Many people have different addresses listed, and it's hard to keep up with the changes. If you can, contact the person and ask them directly. The next best way to find their address is through People Search . Beyond that, you may try searching by their organization.
Most colleges have a listing of student e-mail address, sorted by year.
Good luck, and hopefully you'll find the person you're looking for.