I have been coming increasingly to the conclusion that, if one waits for a "good time" they will be waiting forever, my wife was asking me today, why in the world did I wait so long to explain all this to her, and that even with all the hints in the world she seemed to be thinking that I was gay/bi or something. The same with the friends I am out to, they didn't want hints, they just wanted the truth.
Of course, I have no idea how your parents would react, but I daresay most of us tend to assume a worse reaction than we get. So far I haven't really got a negative reaction, then again I have been very unapologetic about things when coming out, If they want to be in my life, they have to support me, or at least tolerate me.
I would however, advocate waiting if you can't come from a position of strength, for example if you are totally dependent on someone it is probably best not to tell them if you anticipate a highly negative response, until you can be independent enough not to be on the street from losing them. I have thought about this alot since I am a rather dependent person usually, but the more I come out to people the more independent I become since I can't be sure of their support until I talk to them.
that's my thoughts on it, YMMV though, and good luck!