Let's face it, here in the USA the cable operators control the bulk of the Internet access to the home, and in essence have the crown of champion of the last mile for the most part. As the gatekeepers to the Internet they have the "power" to control what goes over their networks, versus a real Internet connection from an ISP like client COVAD, which gives you OPEN Internet access.
Much has been written about Comcast and their packet sniffing around P2P file transfers. It's also in my view impacting Skype traffic too. Each day Ken Rutkowski and I record a daily news program. For the past few years we have used Skype over Broadband to connect and for Ken to be able to capture the audio. Of late when Ken is on his Comcast connection we have issues. We switch to his Covad broadband and the issues (latency, packet loss, etc.) seem to disappear. At first we used to think it was my constant changing of Macintosh computers, so now that I go hardwired into the router connected to the Covad bonded T1 (in essence 3 megs symmetrical connectivity) we have seen the problem only manifest itself when Ken is on his Comcast connection. So much for real Internet from Comcast.
I bring this up because the Femtocells and mobile operators will likely run into similar problems if they don't pay a toll to the cable operators and even the telcos in some way because the MSO's here in the USA have a vested interest in Sprint's PIVOT platform which the major cable operators are all slowly rolling out as their fourth fourth piece of the Quadplay offering.
In essence the Femtocell lets the cell phone work indoors, connect over the broadband line, then the Internet provider feeds the call back to to the network of the cellular operator. T-Mobile sort of has this running without the FemtoCell with their UMA platform and it seems to work well, based on my last few months of use. But where the Femto cell differs is that it's not VOIP, its just an extension of the cellular network. For many, especially in high rise buildings and in hard to reach locations for cell service this will be a great solution.