SNL Kagan forecasts that cable companies and wireless operators will control nearly half of the residential phone market by 2012. In a new study, the market research firm also says traditional phone companies' share of the residential market has dropped to 74% from 90% over the past two years, and will shrink to 51% by 2012. Making the biggest inroads are cable operators, whose IP (Internet Protocol) voice services are expected to have 31.4 million subscribers, or 26% market share, in 2012. Meanwhile, the number of wireless-only households, currently about 12 million, is expected to more than double to 26 million--a 22% share--in that time. Driving the wireless transition are the maturing of more tech-savvy young consumers and emerging technologies that improve service coverage and reduce costs, according to SNL Kagan.--Mark Walsh