Declan at Connotea has a link to a report on CDC's Emerging Infectious Diseases page: H5N1 Outbreaks and Enzootic Influenza. Don't be put off by the title. It's a clearly written summary of the background and current status of avian flu. Significantly, it's co-authored by American and Chinese researchers—a reflection of growing cooperation.
The authors are prepared to write vividly when they need to make a point:
Conventional wisdom about pandemic influenza holds that a pandemic is inevitable and that the only question remaining is "When?" The H5N1 virus continues to evolve and spread, with additional human infections occurring in Vietnam, Cambodia, Indonesia, China, and Thailand. If this virus acquires human-to-human transmissibility with its present fatality rate of 50%, the resulting pandemic would be akin to a global tsunami. If it killed those infected at even a fraction of this rate, the results would be catastrophic.