The NFL Network's Adam Schefter is reporting that the Lions have traded Roy Williams to the Dallas Cowboys. According to The Dallas Morning News, the Lions will receive a first-, a third-, and a sixth-round pick and will give up a seventh-rounder. All picks are for the 2009 draft, giving the Lions plenty of opportunities to start rebuilding through the draft as soon as possible.
UPDATE: ESPN's Ed Werder is reporting that no first-round picks are involved in this trade. That is contrary to what Adam Schefter, The Dallas Morning News, and ESPNews are reporting, so I would stay tuned until something is officially announced.
UPDATE III: In a typical ESPN move, Werder's story has been changed to include the correct information. It looks like the Lions will get three draft picks and give up a seventh-rounder, just as was first reported by The Dallas Morning News.