I cannot hardly believe I'm saying this ... every fibre of my being is calling me traitor ... but... don't blame Jobs for this one. It's not an Apple problem. You'd have the exact same issue on a PC keyboard, or any other sufficiently localised computer. Maybe you've only ever used cheaper, less localised ones with more US-spec keyboards before (as I've had to suffer in the UK! with a Macbook before - THAT was infuriating) or something?
In any case, if it's a PC, try Alt-Gr 8 and 9, on Mac, Option-8 and 9. (Doesn't it have the alternate characters printed on there in small, differently coloured type or something? Oh wait ... Mac... Now THAT's what you can blame their stylistas for - over simplifying it to the point of it no longer being obvious or intuitive). As per that Wiki page, which despite some peoples' implied slurs is probably accurate.
Or just get a US or UK spec USB keyboard to plug into it, whereupon you'll find the square brackets nestled happily between P and either Enter or Backslash.