What is a good, discreet parental control program that logs emails?

Question

One of my friends called me today, wanting me to go through his computer to look at internet history and past emails of his kids, because he's concerned about what they do online. Although I work on computers on a regular basis, this is a first for me. I figured instead of trying to dig up the past, maybe it would be easier to install some kind of logging software to monitor future use. The thing is, he doesn't want them to know they're being watched. Can you recommend a software package that would help with this?

Answer 1

that would be a keylogger running to stealth mode.  I'm a security researcher, so I cannot advocate them.  They are highly dangerous and many worms/virii/rootkits can read the contents of these logs and send them to a remote attacker (think credit card nums, password, etc).  Be careful in what you use.  If you MUST use them at all, make sure the logs get encrypted and require a well chosen password to decrypt them.