Audrey,

>> How do you all know these "meetings" arent just your imagination? <<

  In my experience imagination can perceive information that is real or fantasy.  Knowing whether these "meetings" are real or fantasy is based on:

1. Obtaining information from the deceased that you have no other way of knowing accept via that contact and communication

2. Having that information verified as real.

>> I lost my 30 yr old brother just a few wks ago. I would love to know that he made it and is doing ok. <<

My condolences at your loss.  The most common way for someone like your brother to make contact with you is while you're dreaming.  Knowing if it's a real contact with him can be evaluated in the same way as other contacts.  He might say or do something in the dream that gives you information you have no other way of knowing, and it may later turn out to be proven true. 

>> My sister told me the bible says trying to contact the dead is a sin. Any comments??  <<

What the Bible says appears to depend on who is reading and interpreting it.  It wasn't that many years ago that the Bible said the Earth was the center of the Universe, and that the Sun revolved around the Earth.  Galileo was threatened with dire consequences by the Church for the sin of saying it was the other way around.  Perhaps some day those who interpret the Bible will decide that contacting the dead isn't a sin any more?

Bruce