I recently came out to my mom. I started with hints, then I let her see me in increasingly feminine clothes (we live in different cities, so I able to plan outfits for intended effect) and finally, she worked up the nerve and guessed right: "You aren't going transgender on me, are you?!" in a voice dripping with scorn and dread. That was something I was prepared for, and it didn't hurt me like it would have 6 months ago.
I'm not terribly loquacious in person, so our conversation person was rather brief. Over the next week, I've been emailing back and forth with her. I've written perhaps dozens of pages on the topics of my gender, my perception of it, society's perception of it, and the impact that her actions can have on my well-being. Also, I've been filling her in on the secrets I've been keeping from her for the past year; sharing insights on my childhood and upbringing, etc.
My mom is a prodigious reader. She's not all that talkative either. So for us, email is better. I wanted to do a face-to-face reveal, just 'cause. In coming out, I've had trouble broaching the topic. Once it's out there, I can freely talk about it. I knew her curiosity would boil over eventually... hence the increasingly obvious hints.