I usually talk to mine when I'm in deep meditation. However there have been times when they or deceased people visit me in dreams and give me messages and advice. The messages have always been spot on.
In fact I had been dreaming about my deceased mother recently (Sunday, July 13, 2008) and she gave me a solution to a problem that I had. I applied the solution on Monday morning and to my surprise it worked. Then two days later, someone left a message on my answering machine saying "Jen this is your mother."
and then they hung up. Jennifer is my first name, so I know the message had to be for me and not someone else. And what's weird was that when I traced the call, the number was from my the phone on my desk at work! How can a call I never placed end up on my machine? And no one at work would play a trick like that because they all know my mother passed away last year.