Planet Family Guy mentioned that Family Guy is to start on BBC2 this October, though Rob couldn’t find anything from the BBC to back ths up. I’ve done a little digging, and found a BBC press release from last October.
The release says that BBC bought the rights to Family Guy season four, as well as seasons of Arrested Development and Family Guy-alike American Dad. There’s nothing in the press release about air dates, beyond the suggestion that the new shows will air in "2005/6". There’s also no indication of whether we’re talking about production seasons or broadcast seasons. The fourth production season of Family Guy has been split into two broadcast seasons (the second of which began last Sunday).