According to stories at mylookout.com there is a Trojan malware targeting Android devices. They are calling it "Geinimi". Reports say it permits a remote server to control an infected phone. It is being embedded in modified apps.
http://blog.mylookout.com/2010/12/geinimi_trojan/

Lookout is in the business of selling solutions to this and their report may have a conflict of interest. According to discussions at slashdot the threat is not serious.
http://mobile.slashdot.org/comments.pl?sid=1930156&cid=34713966
http://mobile.slashdot.org/story/10/12/30/1856242/Android-Trojan-Found-Spreading-From-Chinese-App-Stores

that is soooo boring