The sign of the correlation coefficient (+ or -) defines the direction of the
relationship, either positive or negative. A positive correlation coefficient
means that as the value of one variable increases, the value of the other
variable increases; and as one decreases the other decreases. A negative
correlation coefficient indicates that as one variable increases, the other
decreases, and vice-versa.

How to remember it:
If two people are riding a roller coaster, they go up together and down
together.  But if they are riding a see-saw (teeter-totter) one goes up 
when the other goes down, and vice-versa.  For positive correlation, think of
two people riding a roller coaster.  For a negative correlation, think of
two people riding a see-saw (teeter-totter).  :)

Edwin