bbman: The Femto Cell effectively creates a cell site (3G 2100mhz) in your home so your phone can make calls and use 3G mobile data. It is not a 2G solution.
Note that if your phone has WIFI may as well use that, probably be faster anyway but for voice calls it will be a great.
And that is the great hole in this good idea, which essentially makes it a voice only product.
If you have an ADSL connection why would you bother to transform it into a 3g data connection at considerable cost, when you can plonk a WIFI AP on it for a cheaper price and greater speed?....