I mostly agree with Lauren Ipsum, just a couple of extra thoughts:
As Lauren says, John Doe and Jane Doe are widely recognized as fake names.
John Q Customer is often used for a fake customer name.
For US telephone numbers, use "555" for the exchange, like "123-555-1234". "555" is reserved by the phone companies just for use in examples and in books and movies. The other digits then don't matter: you can use a real area code or not.
Lauren mentioned using "example.com" for websites. This is also reserved specifically for examples, so you can be sure there will never be a real site with this name, and it's pretty obvious that it's an example.
I don't think there are any widely-recognized fake addresses. I generally use addresses that sound obviously fake, like "123 Some Street, Anytown PA 12345"
Definitely do not use any real person's information. Years ago I worked for a company that made a software package for doctors' offices, and at one point our chief marketing guy was going to some convention and he dropped by and casually asked me for a copy of a real customer's database that he could bring to the convention to use when giving demos of the product. I went through the roof. You want to use real people's private medical records for a demo at a convention?! I'm sure there are laws against that. Even if it was information not protected by law, you could set yourself up to be sued, or at the very least alienate customers with your lack of respect for privacy.