According to Wikipedia, some people use the term "sociopath" and the term "pyschopath" interchangeably, while others believe that only one of those conditions really exists, and others believe they are two distinct conditions. Basically, sociopathy is a personality disorder formed by social factors, and psychopathy is a mental disorder caused by "a combination of psychological, biological, genetic and environmental factors."
To my lay mind, psychopathy sounds like a true mental illness (meaning, in the way I was using it, an actual biological disorder affecting the mind), and sociopathy a personality disorder (bad programming). But there seems to be much debate.
http://en.wikipedia.org/wiki/Psychopathy#SociopathyI had two brothers. One was (still is) mentally ill (paranoid delusional schizophrenic) and one was (he's dead now) sociopathic. Bush reminds me of the sociopath. I always felt like he could choose to be different, but that society (he was actually a foster brother) had twisted him to be bad. Seung-Hui Cho reminded me of my PDS brother. A few minutes of talking to him, even now while on full medication, and you know he could never be different. (I was adopted, btw, so I have neither of those problems, although someone last night accused me of being a manipulative bully. :( )
Anyway, there are professionals around here, maybe one of them could give much better info than I just did.
(On edit: In the first paragraph, I meant to add that some experts argue that both conditions are really the same condition, with some experts believing one cause, others the other. And I imagine it's even more complex than that. :)