I know where you're coming from, art. I dunno if I'm much help here, since I'm still trying to get the hang of it myself, but as far as initiating conversation, I just try to bring up something obvious that you know you and another person can comment on...like the weather, or if you're in school, talk about the class or something. Usually, I can get at least a good five minutes of conversation out of something simple like "Damn, it's cold in here, isn't it?"
As far as being yourself and opening up...I can see what you mean there, because I usually have to know someone for a while before I really start to open up to them. I don't think too many other people are as loose around strangers as they are around their friends anyway, so I wouldn't stress about that if I were you.