Yeah, I haven't had much experience with telling (I haven't told yet except to my mom), but I've read a bit about it here and there. What may help is first talking about more accepted disorders (autism, depression, dyslexia etc.) to 'test the waters' so to say. Maybe you have one of the more common ones to talk about (I've already had four in my life, two of which were wrong, so I have something to talk about

). When people respond oddly to them, just don't tell them any more.
Another thing that might help is when one of a group knows about it (and accepts it) to talk about it. May help for others to accept it.
I agree with Journalgirl, friends aren't real friend when they don't accept this.
I'm not that socially apt, so take this with a grain of salt (this is an understatement).