Witten will only be a restricted free agent after 2006. He will have only completed 3 years in the league. If a long term contract can't be worked, the cowboys will have to give him the highest tender offer usually around 1.5 million or so for one season, but that means if the cowboys decide not to match a contract offer, they would receive both a 1st and 3rd round pick. The tender is a way to scare teams off from even pursuing. But after the 2006-2007 season is where he would be an unrestricted free agent. Roy signed a seven year rookie deal, that was voidable after 5 years, so he will be eligble for unrestricted free agency after the 06-07 season as well.
So basically, both guys will be eligible for unrestricted free agency during the 2007 offseason.