If you live in Ireland (and, actually, even if you don’t) you can make good use of the new leaflet on migraine put out by the Migraine Association of Ireland. This leaflet is an excellent summary of migraine, its types, treatments, and theories about its causes. [note: this leaflet is no longer available. Visit the link above for other migraine information]
Be sure to visit the site and poke around – you’ll probably come away with better understanding than you came with. The association is 11 years old, and still growing strong.