I've long predicted that Spam Senders and Virus Writers would join forces to create some all round, totally annoying thing, and sure as heck they have.
"German magazine c't says it has evidence that virus writers are selling the IP addresses of PCs infected with Trojans to spammers. Spammers use these infected systems to unlawfully distribute commercial email messages, without the knowledge of their owners."
I am sure its not long before we will have a Spam Network in existance that provides a framework for Spammers to do their evil deeds, and is promoted and maintained directly from Viruses. Its only a matter of time IMHO before these computer nasties merge to form something completely downright infuriating.
More here.