I'm afraid I don't have much advice, myself. It's been something around 5 years since I first cast away my previous Christian beliefs and identified myself as an Atheist, and I've skipped the issue of notifying family by simply not telling them. They're aware that I no longer attend church, they know that I refused to attend with them the last time I visited, but ~3000 miles of distance and the fact that religion, while extremely important to my family, simply isn't much of a conversation topic in our phone conversations, I haven't had to spill the proverbial beans.
I'm avoiding it because I know that it will cause my parents and especially my grandparents pain, and I don't want that.
As you said, Jazzns, I
am the same person, just as you are. There's no need for me to jeopardize their perceptions of me. Of course, I don;t have any children.
I'll tell my family eventually, likely sometime after my grandparents pass (hopefully not any time particularly soon). When I do, I plan to be as gentle as possible about it. Insulting and rejecting a person's deeply held beliefs can be very easily construed as rejecting and insulting the person instead; Christianity and faith are very closely tied with my parents' (especially my mother) identity.
I'm slowly testing the waters already, seeing my parents reactions when I outright reject things like the Flood, refusing to attend church, etc. I don't want it to be "out of the blue." I want them to suspect something is up with my beliefs. And when the time comes, I'll frame the debate myself. I'll explain my reasons, and why saying that I believe in god(s) would only ever be a lie, even if I tried to tell it to myself. I'll tell them that they're still my parents, and I still love them, but that I am no longer sufficiently convinced in the veracity of Christian dogma to say with any honesty that I believe it; and that I would consider attending church in such a state of disbelief to be dishonest. I'll explain why I still have a strong sense of morality without god, heaven, or hell, and why I find myself caring even
more now for the well-being of others.
And then we'll see how they feel.