Embracing a technology that has unnerved media and telecommunications companies, a major European wireless provider will let customers watch their home cable TV on a cell phone if they also have a device called the Slingbox back at the house. 3 Group will launch the new service in Britain first, starting December 1, followed by three more of its 11 markets in early 2007, the wireless company announced Thursday. Two new handsets running on 3’s next-generation wireless network will feature the Sling application, which customers can use to watch any channel available on their cable TV at home. The phones also can be used to control a digital video recorder at home, pausing and rewinding live television, playing previously recorded shows, or setting up the DVR to record a program.