Not some nutjob conspiracy theory, but something proposed by a reputable scientist and being investigated by the WHO:
http://www.bloomberg.com/apps/news?pid=20601082&sid=aShZig0Cig4g
http://www.bloomberg.com/apps/news?pid=20601082&sid=aShZig0Cig4g
The World Health Organization is investigating a claim by an Australian researcher that the swine flu virus circling the globe may have been created as a result of human error