Hi Andy, speaking for myself, I started out learning to use continuous lighting with the camera on a tripod taking pics of things that don't move. With continuous lighting 'what you see is what you get' and you have less to learn about composing the shot before pulling the trigger. I learned tons about how white balance effects different lighting types ie, tungsten, incandescent, compact flourescent bulbs and daylight, faffing around with this not to mention just how genty you can light things.
I have just started to use flash and so far I find I don't need a tripod so much as I use a faster shutter speed. I am still messing about with brollies etc and would say that working with flash is harder to learn than continuous. For glossy products against a white background continous lights are still better for me but with satin or matt surfaces, flash is a doddle.
Visit Strobist.com, as has been suggested
Continuous = easier to compose a shot, shedloads of ways to play with the light and learn, plus you can build the light slowly.
Flash = a right old learning curve composing shots and controlling it at first. It seems to me you start with the maximum light possible and then trim and shape the shadows by diffusion and gelling etc , seems like its all about compensating for high speed and power. Same end result more or less as continuous, just a different and I would say, larger skillset with more professional looking kit.
Thats where I am wiv em.