"Just make the person you want to steal from send you an e-mail and you get his ip. From there, "all you have to do is to implement a Trojan on his computer".
That is the most ridiculous thing I've heard in a while. Having an IP doesn't really help you get into a computer at all - you'd need some security hole to exploit or an extremely stupid user (more likely to find the latter). But let's be honest here, most people using Bitcoin at the moment aren't the clueless type I'm referring to - you'd be better off phishing for card/bank details and probably have more success there.