I don't know if we're getting busier (stats don't seem to show one way or the other) or if we've just promoted too many of our active users to moderators, but the past few weeks the review queues have started to get relatively full for a site of this size. This morning, the number up on top of my browser was a 15 when I logged on, which is pretty big for a beta site with 4 questions per day.
If you have at least 350 reputation, you can begin monitoring the review queues, accessed from the "Review" link up on top of the screen. At 500 and 1000 you'll get access to more tasks you can do. If there's a number up by the review link, that's how many items are in the queues right now; that's not always how many you can act on (as some tasks require 2 or more people to review them) but it's a good indicator something's there to look at. You can also get some shiny1 badges as a result of completing certain numbers of review tasks!
Much of what reviewing involves is simply reading posts made by new users and giving them feedback - either positive or negative. Many new users aren't familiar with the StackExchange model and/or with specific elements of Parenting's take on the model, and so it's helpful to guide them towards writing more useful posts. Reviewing posts that need to be closed or re-opened as well as suggested edits is also very helpful to help keep our site neat and orderly.
Don't forget this site (as with all StackExchange sites) is primarily self-moderated, meaning all of us contribute to the moderation - not just those with the fancy diamonds. It's important for all of us to periodically help out - a couple reviews a week takes only a minute or two and would help make sure new posts are given the feedback they need. Erica, Rory, and Anongoodnurse only have so much time to spend on review activities - and they've got quite a bit more to do than that.
If you have questions about what a review queue is, take a look at this question and answer over at Meta.SE for more information. Thanks, and happy reviewing!
1Badges are not actually shiny.