Don't send computer viruses.
If you have an idea for a fun Trojan horse, don't send it.
If you have an idea for a virus, don't send it.
If you have a great idea for a worm, don't send it.
If you think you have a way to get someone's information by using spyware, don't do it.
Don't tell people to get anti-virus software.
Don't tell people not to open suspicious emails.
Don't tell people to install security updates.
Don't suggest that it is your responsibility to protect yourself from computer viruses.
Don't perpetuate a "hacker culture" by telling people that anyone except those who write computer viruses have any responsibility for stopping them.
Consider these ideas for a moment, then read this (note: link is dead - 09/16/09).
That is all.