I have people sending me spam mail using my email address as the sending address. Isn't this illegal?

I would like to know how you can forward this to someone who can stop it from happening. Or someone who can do something about someone performing this form of fraud and identity theft.

There is no such thing as an internet police force. It's wild west territory and completely unregulated. You might see if your ISP can help, but I doubt it.

This is called a "Joe job," Google it for details. Heck yeah it's illegal. But most of these come from compromised computers so there's no way to catch them.

The way it works is: hacker gains illegal access to a computer or server. The compose a mail from this compromised machine, and use an available email address in the from field, even though it's not from that person. You can see the actual origin when viewing mail headers, often it will be anonymous@some-hacked-domain-name.com.

The recipients don't know well enough to view headers, or know what they mean, all they see is the from address, hit reply, and scream "stop spamming me, I don't need Cialis!" Which is probably how you found out about it.