The usual form of this phrase is:

La corneille, perchée sur la racine de la bruyère, boit l'eau de la fontaine Molière.

Read the links (or Jennifer's previous writeup) to see the names of the most famous 17th-century French writers. It's used sometimes in French schools, mostly for fun because you don't really need these mnemonics to remember these names when you are French...

As Jennifer said, the meaning is: The crow, perched on the heather root, drinks the water of the Molière fountain.

There really is a "fontaine Molière" in Paris, at the corner of rue de Richelieu and rue Molière in the 1st district. It's located one block away from the Comédie Française which mission is to play Molière's repertoire. At you will see the fountain, but no crow on a heather root.