Answer by TinyUtopia

PlayerPrefs Class is also very helpful if you want to save any of those variables for use in multiple game sessions.

Full details are here: http://unity3d.com/support/documentation/ScriptReference/PlayerPrefs.html

but the easiest way is to use something like this:

static var scorevar: int; 

function saveScores()
{
PlayerPrefs.SetInt("HiScore",scorevar);
} 

function getScores()
{
score1 = PlayerPrefs.GetInt("HiScore");
}

The word "HiScore" used in the example is just a key for setting and retreiving the value (int) that is saved. In other words, you can make it anything you want. You can save other data like strings if you use the correct sub class, all these options are listed in the player prefs script referance.