To earn a save the pitcher must
A. Pitch last for his team in a game his team wins AND
B. Not be the winning pitcher AND
1. Pitch at least 1 inning (3 outs) with no more than a 3 run lead OR
2. Pitch with the potential tying run on base, at bat, or on deck.
So basically, part C.2. is the tricky part. I think of it this way: if the number of men on base + the number of outs remaining in the 9th is equal to or less than the lead, then a save is earned.
Example: 2 on, 1 out, 4 run lead. Closer enters the 9th and gets the final 2 outs and he gets a save. 2 on + 2 outs remaining equals the lead of 4. 1 on, 1 out, 4 run lead. Closer enters the 9th and gets the final 2 outs and does not get a save. 1 on + 2 outs remaining is less than the lead of 4.
Hope that helps.
Also see http://mlb.mlb.com/NASApp/mlb/mlb/offic ... ations.jsp
I think your interpretation of the rule is flawed. The number of outs is irrelevant.
Basically, if he comes in, if the man on deck would tie the game (or take the lead) then he earns a save.
So it's not runners on base + outs, if it's whether the # of runners on base + 2 (batter and man on deck) equals the lead.