So this article came my way via SETI@Home, of which I've been a participant in since 1999. (Yes that's right, computers that I have owned have processed over 32,000 work hours of data for the project over the past 13 years or so...what can I say, I am a Flagrant Nerd!)
It's kind of an interesting article and a pretty good read from io9.com regarding whether or not the SETI (Search for Extraterrestrial Intelligence) or METI-type (Message to Extraterrestrial Intelligence) projects could possibly download a malicious virus from an extraterrestrial source.
Contact (the movie version of which was a so-so flick but the actual book is great!), there actually have been ideas of this sort going back to the 1960's (the article mentions A For Andromeda and His Master's Voice). io9 talks to two experts on the subject of SETI, Andrew Siemion, a PhD candidate in astronomy at SETI-Berkeley, and Milan Cirkovic, Senior Research Associate at the Astronomical Observatory of Belgrade and a leading expert on SETI.
Give it a gander...it's some interesting stuff...though I fear I am in more danger of some damn teenager in China hacking my Xbox.com account (that actually happened, which reminds me, Xbox and Microsoft never refunded me the $50 he stole like they said they would) than I am of an alien from Alpha Centauri sending a trojan horse to my laptop.