The Aurora Sentry site provides real-time maps and magnetograms, with links to the data sources. You’ll probably want to check out the link for "Alert Services," which lists several e-mail notification services. Notices go out when geomagnetic indexes reach certain levels, or when an especially strong gust of solar wind is heading our way.

These services are only as good as the diligence with which you check your e-mail. As technology marches on, however, some cellular phones are gaining e-mail capability, so you could set yourself up to be signaled by phone. That is, if the magnetic storm hasn’t knocked out the network (Sky & Telescope: March 2000, page 50)!

Calling observers about auroras and other sky events is the goal of another longtime online resource. Spaceweather.com has provided geomagnetic information and predictions for years. Now it has branched into another medium with SpaceWeather Phone. Sign up for their service and, for a fee, they'll call you when things are happening in the sky, including displays of the northern lights. Of course, this still won’t excuse you for keeping your cell phone on during a movie.