Hello! Everyone! My boss asked me to install some monitoring software on our office computers(XP), but I've no idea where to start looking, does anyone have any experience with a decent one? I've tried the filters built into IE but they are terrible...

I have searched google and got some like these

Employee monitoring  

remote spy software

But there're much more..I have no idea.. Could some master tell me how to choose a reliable one from the internet??