Where: Although there are schools in Utah, Oregon, and there's a pretty intimidating club in Colorado, the best of the best is in Switzerland.
Aspen Speedriding Club logo:
When: Ski season, wherever you are
How: Step 1: Learn how to ski. Step two: add kite.
Name Game: I like "speedflying" because it doesn't explain how you'll fly speedily, and "speedriding" isn't much better. Don't confuse it with kiteskiing (more about tricks, less about falling), or wingsuit skiing (base jumping with a wingsuit and skis, which has only been attempted once in Norway according to these people).
Some insane videos:
Disclaimer: Half of the speedflying videos or websites I've seen have an "in memory of..." portion. One of the founders of the sport, Mathias Roten, died speedflying in 2008.