It doesn't really work like that as the sports book will "move the line" until there is even money bet on both sides. The book does this because they make $5 on every $100 bet and the only way they can be assured of making their percentage is to get the same amount of money bet on both sides.
Saturdays Utah BYU game is a good example. The opening line was BYU -2.5 (which means BYU was favored to win by 2.5 points). But after Utah played descent against ND and BYU's trainwreck against LSU and troubles against Portland State, folks noticed Utah was a good bet and money starts pouring in on the Utah side. The sports book doesn't want an unbalanced bet so they move the line to where Utah is favored by 1.5. So this causes folks to start betting BYU which will even out the money bet. The sports book will keep moving the line until the money bet on both sides is relatively even.
So if you want to make money betting you don't bet your heart or your favorite team, you bet when you see the sports book made a mistake when setting the initial line, which they did with the BYU Utah game. Which is why I bet $100 on Utah and I get 3 points (BYU must beat Utah by 4 for me to lose my bet).
The current money line on Utah BYU is currently Utah +125, BYU -105. This means Utah is favored. If you bet $125 on Utah and they win you receive $200. If you bet $105 on BYU and they win you receive $200. Notice the book is charging you $25 to bet Utah and $5 to bet BYU, and again they will move the line until the money bet on both sides is equal.
A couple other things to consider....
Seldom/never do you find a book taking bets when a power is playing a cupcake. They will post the odds, but it is "off the board", which mean they will not take bets on the game.
Home field in college is usually worth +3 points with the sports book. Which means if Utah was playing at home this weekend they would probably be favored by +4.5.
And to answer your initial question about BYU against Wisconsin, BYU is currently a 10 point underdog, so if you bet Wisconsin they must beat BYU by more then 10 points for you to collect your bet.
And just for fun, look at Ceasar's Palace on this page:
http://www.vegasinsider.com/college-...9-17/time/2215
And you can see where they moved the Utah BYU line three times yesterday (9/6) to get the money bet to even out.
:soapbox: