Check out this article from the New York Times.
Google is tracking flu outbreaks by web info searches. Here is the best part
"A paper on the methodology of Google Flu Trends is expected to be published in the journal Nature."
Very cool./
Here is the link:
http://www.nytimes.com/2008/11/12/technology/internet/12flu.html?em
Omai
It is nice.. There is also a integrated system for joint surveillance against the emerging or Epidemic diseases in Tamilnadu, India
http://www.edis.zampbioworld.org