Sorry...little more explanation...(there is a thread somewhere about ILB's in the 3-4 )
The starting "ted" linebacker will be Brandon Moore, who played extremely well after moving into the starting lineup midway through the season to replace Jeff Ulbrich at right outside linebacker in the team's 4-3 defense. Moore was named NFC defensive player of the week for his performance against the Vikings. He had 15 tackles, two forced fumbles, a sack and three QB pressures. Moore led the 49ers with 114 tackles and 6.5 sacks. In nickel situations, he lined up at defensive end to rush the passer. Although he said he probably will not be asked to do as many different things this season, he believes he will see some time at defensive end in nickel situations.
****
Smith and Willis are competing for the "mike" position, which is the inside linebacker on the weak side. The other inside position is the "ted," which lines up on the tight end side. The "ted" will have to sift through more traffic, while the "mike" should be the position that makes more tackles because he won't have to contend as much with guards or the fullback.
Link
http://49ers.pressdemocrat.com/default.asp?item=643537