In response to my comment about having a load of interviews and things about Alan Moore and magic bookmarked, someone (I don’t have the email on this computer, so I apologise for forgetting who) asked me to make the links available. I live to serve.
Alan Moore interview at Eddie Campbell comics. The Magic of Alan Moore website – a good collection of info from various places about Alan and magic, including his correspondence with Dave Sim on the subject. Another interview at blather.net, this time. Another site with a load of collected bits about Alan and magic (including the aforementioned correspondence) is available here.