What is the best way to locate a person online for free?

Question:

What is the best way to locate a person online for free?

My friend is trying to track down his dad. Does anyone know of any websites that aren't scams to pull up things like addresses and phone numbers?
Also His dad was in the Navy are those records public?

Best Answer - Chosen by Asker: The best way to do this is to Google. Use details. I tried finding a girl I'd lost touch with, by Googling her name and location "Mary Jane Utah". Anything you know about them. Google is great for that. I also find MySpace has a lot of people (but don't go there with Internet Explorer...too much Spyware...use Safari [www.apple.com/safari])

Hope that is helpful.