This just in. An article at Globes Online describes the arrests of executives at three large Israeli companies for hiring "private investigators" to spy on competitors. The private investigators are also charged for using Trojans to install spyware on machines within the competitor's organizations. An even better description of the incident is at Haaretz.
Note that a custom Trojan was designed for the investigators. While custom malware can avoid detection by signature based systems, typically an anti-spyware solution will pick up on traces of commonly re-used elements that a hacker would stitch together.
It is becoming easier and easier for someone to attempt espionage via computer cracking. The programs are available commercially and are designed to install without leaving any traces.
Organizations should take step to prevent this type of attack. An anti-spyware solution is required to do this effectively. Firewalls should block outgoing communications initiated over most ports.
Have you recently had to let an IT staffer go? Do you suspect that this person would either seek revenge or in some way try to hack back into your systems? Another good reason to do a spyware audit on your Windows machines.