It's the same as the 'Steam' system used by Football Manager 13 (the better game by far incase that wasn't clear). You'll have unlimited installs on as many PCs as you like, as long as you do it all through your own personal account which you are signed into whilst you're playing the game.
DONT BUY THIS GAME.
Buying Football Manager 13, it is the ONLY, option for PC Management games.
Regarding the question, the serial code will be applied to an EA/origin account. You'll then use their software to download and install the game as many times as you like on as many PCs as you like...