posted 12-17-06 03:49 AM EDT (US)   
To cast at twice the speed without having to train in Quickened Casting, press your "stop current action" hotkey as soon as your Firebolt (or Icebolt or whatever) goes off. You can cast another immediately without having to wait for that annoying animation latency. Surely, training in Quickened Casting will make this even faster, perhaps even funny. Try it out now, since now that I've spilt the beans they'll probably fix this "bug" in the next patch (should there ever be one!).
cheerio