I could write a ton on this topic, but I'll try to be as brief as possible and answer your question.
Baseball lines can be expressed in two ways: Money Line
(mostly used in Vegas or online gambling sites) Odds
(mostly used by local bookies - or at least the ones I have dealt with).
Bottom line is that they are one and the same, just two different ways of expressing it.
The Money Line:
The money line is easier to understand for the newbie or average bettor.
Quite often you'll see a money line of: Toronto (+120) AT Cleveland (-140).
If you bet the favorite: Example...you would bet $140 on Cleveland. If you win, then you win a net of $100. If you lose, then you lose all $140 that you bet.
If you bet the underdog: Example... you would bet $100 on Toronto. If you win, then you win a net of $120. If you lose, then you lose the $100.
Note: You can bet whatever amounts you want. I chose the figures I did because I wanted to keep all the examples on a $100 scale.
On the other hand, when dealing with a bookie, he will most of the time use odds as they are easier and faster to say over the phone than all those hundreds.
So when the bookie gives you the line on the game (using the same game example as above) he will say (this may certainly vary depending on your bookie):
"Cleveland 6 - 7" (This is much faster than saying: "Toronto, plus one-twenty and Cleveland, minus one-forty")
The format is: 1) Name of the team that is the favorite. 2) Underdog odds. 3) Favorite odds.
The entire system is based on the number 5. The underdog in the above example (Toronto) is at 6:5 odds. The favorite is at 7:5 odds.
Note for beginners: It is understood that the payout for the favorite is less than your actual bet and that the payout for the underdog is more than your actual bet. The only time this would not be the case is if the line was said to be an even money line, in which case normal juice applies.
Since the system is based on 5, you would multiply each of the odds (6 and 7) by 20 in order to make the system based on $100.
6 x 20 = $120 and 7 x 20 = $140 and that is how you get the money line.
Now if you get a pitching matchup that is really a mis-match like a Johan Santana at home (after 4 consecutive Santana wins) versus the Royals who have lost 8 straight games and are starting a rooke pitcher..then you could see a line as high as 13-15, or even higher.
Basing this on a $100 bet, this would mean:
You would wager $100 on the Royals to win a net of $260.
You would wager $300 on the Twins to win a net of only $100.
For the poster above, if you're wondering how the money line on the Bulls was (-1400 and +900), my answer is simply that whoever is making the lines really want to cover their butts. Usually you will see odds/money lines like this if you are betting on an entire 7-game series in the very early rounds of either the basketball or hockey playoffs. Vegas is basically trying to maximize the amount you have to pay to bet on the favorite while minimizing the amount you can win on the underdog, in case they do happen to win. These certainly are extraordinarily high odds and without knowing exactly which game you're referring to, I would have guessed that 1400/900 was the one of the series prices for the Bulls in their opening round series against whatever crappy 8th seed they were playing.
If you translate that money line to odds, it comes out to 9 - 14. Usually when the underdog is 9, the favorite is 11. But given how strong the Bulls were back then, Vegas decided to up the ante by making them ridiculous favorites of 9 - 14.
So essentially you had to put up $1,400 just to win a net of $100. YIKES!!!