LSU got in because of all the crazy stuff that happened that final weekend of the season.
#1 Missouri: lost to Oklahoma in the Big 12 title game for their second loss
#2 West Virginia: lost to 3-8 Pittsburgh for their second loss
#3 Ohio State: idle
#4 Georgia: idle
#5 Kansas: idle
#6 Virginia Tech: beat Boston College to win the ACC
#7 LSU: beat Tennessee to win the SEC
OSU jumped to #1 because of only having 1 loss and LSU jumped to #2 because they killled VT earlier in the season and had a better resume than both UG and UK.
Anyhoo, that was under the old system and is irrelevant. The bottom line is OSU is in. 3 top 10 wins (2 on the road) and their loss was @ another top 10 school who was coming off a bye week by 3 or 4 points.