There are many internet service providers specially for children. You can visit down to avail internet services for your children. Kidsemail.org helps you ensure that your child communicates with contacts approved by you. They offer these services at lowest possible costs. They offer free trial service for 30days, i.e. a month after which you can decide whether or not to continue with their services. You will get details on discounts and refunds from their site.

Here is a link that might be useful: kidsemail.org

If you are worried set up a google or yahoo account, to sign up, you can check but not clutter up your normal account, that said biggest security if the computer is set a public place, ours are in the kitchen and family room our boys can explore but we can over see

If your computer has Window's Vista, it has some nice built in features. One of them is the ability to check on their account (assuming they have and use their own account rather than a shared family account). This only works with Internet Explorer, but it will show you what web sites they have visited.

Not quite what you were asking, but it's a neat feature parents get for free if they are using Vista.