some folk manage to learn on smaller conventional boards, and some swear by the big ones you have been recommended. I think you'll definately find the big one easier for learning basic balance, uphauling, and sailing along off the plane, but may grow out of it pretty quickly, especially if it is a Starboard Start model. They are overly big and stable, and even experienced sailors find them awkward to ride when they are on the plane, and make things harder than they should be. Once plaing, the Start model doesn't give a realistic sensation of a conventional board. Personally I think the Starboard GO is a better choice as it is still fairly stable and robust for learning, but performs much more conventionally when planing and you won't grow out of it as quickly. I think they cost a couple of hundred more. However, having said all that, I'm told the 2006 model Start has been improved.
back in the eighties the trend was to learn uphauling, light wind tacks, and flare gybes (turning maneuvres) before you learnt to plane in the harness and footstraps. Many people gave up while learning because learning to flare gybe and tack could be quite hard (
the new big boards do make it a bit easier), and learning it on a big board didn't mean you could also do it on a short (conventional) board, so basically you had to learn it all over again once you progressed to the short board, so you might as well just learn it on a short board to begin with (learning on a short board then doing it on a big board is easy). These days it seems that alot of people (kids especially) move straight onto simply learning to uphaul, beach starting, getting into the harness and and straps, then immediately onto the plane, and leave learning the turning maneuvres till later. I think this is probably a good thing if your in a safe area like the broadwater here on goldcoast, because it lets you move straight onto the fun bits of windsurfing. In this case, you could learn on a smaller conventional board right from square one. In fact I've met several adults who have done just this over the last couple of years. Basically, you sail away from the beach till you fall in, uphaul, then continue sailing in whatever direction you uphauled in until you reach a sandbar, then you just hop off and turn the equipment around, and do it all again in the other direction. You'll probably find this much more fun than trying to learn the 1980's way. Don't forget to learn to gybe and tack once you get the hang of planing in the straps and harness, otherwise you'll be getting off at the sandbars to turn around for the next ten years, and there are many still stuck in this routine

Cheers
H