There are a few things to start with before I really get in deep. Part of your target audience is very young children who may not be readers yet, or whose reading skills are going to be minimal at best. That means that having the same icon shape for all of the actions isn't going to work for a lot of them. You probably want to have parental involvement with the younger kids, but it should be at the assist-and-encourage level rather than at the "here, let me do that for you, sweetie" level. Giving them things they can recognize easily while giving them a chance to make the word/thing connection themselves over time will help a lot.
Having just a blue-to-green range for colour changes won't work for a lot of them either; even if they have perfect colour vision, youngsters may not have developed subtlety of colour identification yet. That is, they may be able to
see a difference without actually
understanding that the colours are actually different. Colour and tone depend a lot on context, and until kids can really appreciate that the context is the same for all of the icons, they may not be able to perceive the colours as different. There's a reason why things aimed at youngsters tends to be a riot of bright primary colours; it translates well for those with colour vision deficiencies, and it takes that whole context subtlety thing out of the picture. There are online colour blindness simulators that can help, and there are tools built into some graphics programs (Adobe is pretty good with this) to do the same thing.*
Three to eleven is a pretty wide range; you're probably going to want to subdivide things more finely. The tricky part is going to be doing it without overly restricting the ambitious or precocious little ones or making the older kids whose tastes are simpler or who may be lagging in some areas from feeling inadequate. (If they have problems, they are already aware of that to some degree at least, and don't need to be reminded of it by having to click "the baby icon".) Understandably, this is going to be the hard part.
I have a problem with Barton's words being graphics in a word bubble. Part of the problem is that antialiasing isn't handled well, and some of the letters are pretty blurry. If you're going to do that (as opposed to using real text), then the words should be the ALT text of the image so that screen readers can access it. We always need to keep in mind, especially with kid-oriented sites, that some of our users are going to have at least some degree of handicap. That doesn't necessarily mean a permanent disability when you're dealing with kids; it could be a developmental delay, a temporary and correctable vision problem, or any of a number of other things as well as, well, blindness or severe dyslexia. We are at a point in technology where we can minimize the impact of even severe disabilities on people's ability to participate in the wider world, and especially with a kids' site, we ought to be doing all we can to level the playing field (without crippling the experience for anybody).
Finally, I can't think of a good reason why the About, Setup and Contact items should be available on all pages. They're just clutter most of the time, and if a kid should click one they're going to be confronted with a big wall of text. For the same reason, I'd make the Parents Page link look distinctly different from anything you expect the kids to use, and probably move it out of the kids' link group.
(At about this point, you're probably thinking that it's a good thing this isn't the in-depth review. And maybe worrying about what
that might entail. Honestly, I'm trying to give you things to build on, not trying to tear you apart.)
______________________________
* If you're wondering how big a problem this can be, try taking the
Isihara colour vision test and the
FM 100 Hue Test yourself, then get a few friends to try it as well. You'll likely be amazed at how many people who think they can see colours well have some pretty deep deficiencies.
Helen