If the schools close...

The swine flu currently spreading around the world has the potential to become a pandemic, according to the WHO. Back during the last flu pandemic in 1918, which was more deadly than all the wars of the 20th century combined, schools in many places shut for long periods of time. Already, individual schools in Texas and New York where outbreaks are suspected have been ordered to close, as well as all schools in Mexico City. If schools in more areas were ordered to close even for a relatively short period during April or May, it would create a significant disruption since most schools conduct end-of-year testing during those months. What could/should schools do to avoid disruption in the event of mandatory school closures? Are any school districts you know of capable of using online instruction as a serious alternative for most students?