Junior ISAs become available tomorrow. To be honest, it's probably not going to be enormously exciting to many people. The reason that most people don't save enough for their children's futures doesn't really have a lot to do with whether any interest will be taxable or not - it's more usually to do with them either a) not having enough cash or b) preferring to use the cash for short-term gratification rather than long-term planning. And, even for those who do save for their kids' university education or whatever, the idea of handing the whole balance over to their child on their 18th birthday may seem a bit risky, to say the least. So at the moment Junior ISAs look like a bit of a gimmick. At the moment there's only a couple of providers offering them in any case, so it'll be a while before it's possible to really say if there's been an enthusiastic take up.
For people who are more interested in saving money for a child but who don't want them to be able to blow the lot when they're 18, a stakeholder pension for the child could be a more tempting option.