DALLAS, Texas - Nebraska redshirt freshman Matt Keller was named the Big 12 Conference Wrestler of the Week for the week of Feb. 16-22, the conference announced Monday.     Last week, Keller recorded his second fall of the season as he defeated 18th-ranked Mimi Miller of Oklahoma at the Bob Devaney Sports Center in Lincoln, Neb., before a season high crowd of 2,072.  The McDonald, Tenn., native pinned Miller in five minutes and 24 seconds to lead second-ranked NU to its first victory over No. 11 Oklahoma since 1999.  The Huskers edged OU 25-12.      With the victory over Miller, Keller won his team-leading seventh match over a ranked opponent and his 23rd overall, which ties him for 10th place on the all-time freshman season wins list.     Keller is 23-8 overall and 13-4 in duals this season. In addition to his two falls, he also has posted four major decisions and two technical falls.     Nebraska improved to 19-2 with last Friday's victory, and won its 10th home dual in the 2003-04 season, finishing the season undefeated at home for the first time since the 1991-92 campaign, and for just the fourth time in school history. NU also won its 14th straight home dual, tying the record that was set in 1989-90.     The Huskers return to action Thursday as they travel to Ames, Iowa, for the season finale against third-ranked Iowa State beginning at 7 p.m.     2003-04 BIG 12 WRESTLERS OF THE MONTH / WEEK  November: Travis Paulson, Iowa State  December: Travis Pascoe, Nebraska  Jan. 12: Chris Pendleton, Oklahoma State  Jan. 20: Johny Hendricks, Oklahoma State  Jan. 27: Jacob Klein, Nebraska  Feb. 2: Nate Gallick, Iowa State  Feb. 9: Jake Rosholt, Oklahoma State  Feb. 16: Tyrone Lewis, Oklahoma State  Feb. 23: Matt Keller, Nebraska