From my experiences on an old sports forum that I used to peruse, I know that not everyone knows and understands the terminology of sports betting. This little mini-guide should help everyone out:
Point Spread: The difference that the winning team needs to \"cover\" or surpass for a bettor to win their bet. If they are betting on the underdog, its the number that the losing team needs to \"cover\", or lose by less than.
Being the Favorite: The team that is \"Favored to Win\" in any given contest is denoted by a \"-\" in front of the number they are favored to win by.
Being the Underdog: The team that is \"Expected to Lose\" in any given contest is denoted by a \"+\" in front of the point spread.
An Example: The Wolves are favored to beat the Spurs by 10 points:
Spurs +10
Wolves -10
See, simple!
Money Line: Let's say its the Raiders against the Colts. If a moneyline is posted, the lines may appear as follows:
Colts -120
Raiders +240
By clicking on either -120 or +240, you are betting on who you think will win the match outright. To win $1 on the Colts, you must wager $1.20. If they win, you get $2.20 back, the $1.20 you bet plus the $1 you won. If you bet $1 on the Raiders and they win, you get $3.40 back, the $1 you bet plus the $2.40 you won.
Parlay: A parlay is a selection of two or more wagering outcomes, all of which must win for the play to be active; the more teams you choose to parlay, the better the payout...but the lower the chance of hitting.
Teaser: A teaser is a combination of two or more football/basketball spreads/totals where you choose a better line on each pick in exchange for a lower payout. Generally you can tease football lines 6, 6.5, or 7 points and basketball lines 4, 4.5, or 5 points
Proposition: A prop or proposition bet is a wager with two or more outcomes that are not directly related to the final score of an event.
Futures: Futures are single wagers placed on the outcomes of events to be determined in the future. For example, betting on who will win the NBA Finals at the beginning of the season.
Here's a pretty good gambling article by Simmons. This should be here:
http://sports.espn.go.com/espn/page2/story?page=simmons/070921&sportCat=nfl 
