The computers most at risk are dormant computers connected to the Internet... (tucked away in a library corner or something)
For the average PC user who has an anti-virus software, updates windows regularly and scans for spyware etc... you'll likely be fine.
Until the virus launches they really don't know what the creators plans are. It usually turns the computers into "bots" that the hackers can then use to send spam, attack other websites with a dns attack (sends so many visits from the dormant computers it crashes the site)
Viruses are a lucrative business right now... With some of these guys making pretty phat cash.
Carl