No "special" stencils required. I live in Australia and they sell them at Spotlight. I attended a Craft Fair at the weekend and bought several - same as the ones I'd seen at Spotlight.
I haven't used them yet but want to be ready for some nice predetermined stippling when I've got my top done.
Still not sure if I'll use the chalk and pouncer I was sort of pressured into buying at the Craft Fair - kind of messy. I may just use a pen. I think that would suit me better.