We have the the five [Lagrange points](http://en.wikipedia.org/wiki/Lagrangian_point) (let consider Earth and Sun):

* $L\_1$ - lie between Sun and Earth;
* $L\_2$ - beyond the Earth;
* $L\_3$ - beyond the Sun;

And what's the difference between $L\_4$ and $L\_5$? Does they defined with the respect to rotation of Earth around the Sun?