Finding the right movies and TV shows for your kids to watch can be challenging and time-consuming for parents and, if you rent a lot of movies, also expensive.

Netflix, the company that revolutionized DVD renting with its “keep it as long as you want” service that sends DVDs by mail, now lets you – and your kids – watch movies and TV shows instantly on a PC or on a TV set.

To watch on a PC you need a Windows PC running Internet Explorer. To watch them on a TV you need a set-top box that connects your PC to the Internet via Wi-Fi a wireless network or an Ethernet cable.The first such box is the $100 Roku – a small device that is easy to set up and use. You simply connect it to your PC and set it to communicate with your home broadband network. Microsoft and Netflix have also announced that, beginning this fall, owners of the Xbox 360 will be able to use that device to watch Netflix movies on their TV.

To use the service you also need an unlimited Netflix account, starting at $8.99 a month. And, unlike other online video "rental" services, there is no charge per movie. You can watch as many movies or TV shows as you want for the single monthly fee.

Unlike Netflix’s 100,000-title DVD library, the instant service gives you access to only 10,000 films. You're unlikely to find the latest blockbuster films, but there are some great and relatively current movies. What’s nice about this for parents is that there are plenty of programs suitable for kids.

The service allows you to pick movies and shows by genre, including the "Children & Family" category which makes it easy to select programs that you want your kids to be able to watch. There are some classic, albeit dated, kid-friendly TV shows such as "Leave it to Beaver, as well as current kid shows from PBS kids and other networks.

The service requires you to use Netflix’s website to add shows to your queue. Once you order them online, they’re instantly available on the TV set. As an adult user I find this extra step slightly annoying—but for parents, it’s actually a good thing because it means that kids won’t have access to any programming from the box unless the parent adds it to the queue.