Not really a worm (it's actually a Trojan-bearing e-mail), but it's certainly a storm. Spotted in the wild on Jan. 17, the executable file reportedly infected more than 300,000 PCs within a week. That rate of infection would make this the worst outbreak since Sober.O back in spring 2005.

What are other companies calling it?

F-Secure first identified the worm and called it the Storm Worm, based on its original subject line. Several aliases for the Trojan have been identified and grouped as Small.DAM. Other nomenclatures:

FrSIRT -- Downloader-BAI!M711 (via McAfee)

McAfee -- Downloader-BAI