Femtocell is the name of the technology being used by Optus in its Home Zone product, which is designed to boost your mobile phone reception in your house.
It sounds like it would be ideal for those of you who are living in regional Australia or in a weak reception spot in one of the capitals. A couple of people who listen in on my tech spot on 2GB have got the devices and say they work a treat.
A couple of downsides are that you can only use it with Optus, which means they have a monopoly, and it is only available with 30 metres of the Home Zone unit. If you go outside the range it will select your normal network.