The Big Ten system basically consists of an official stationed in the press box monitoring the game via TiVo. If he considers a call to be questionable, he will stop play ... not the victimized head coach. The press-box monitor will then review the play via TiVo to evaluate the validity of the call.
The upside is that the monitor official can review the play as many times as he wishes. The downside is that he will only have one angle on the play -- the one provided by TV.
Gaston said the SEC will keep a watchful eye on the Big Ten's replay system this season, then consider the possibility of adopting a replay system of its own for 2005.
Historically, instant replays have shown that on-field officials make the correct call a remarkably high percentage of the time. There are notable exceptions, however, and these mistakes occasionally affect the outcome (see Jabar Gaffney's controversial catch at the end of the 2000 UT-Florida game).
Instant replay is nothing but a bold experiment in the Big Ten this fall, but it likely will become a fact of life in college football in the very near future.