Levicorpus

[Ronda]

Goodasitgets:
When do we learn the Levicorpus spell?  My 14 year old noticed that 
Ginny used it against the Death Eaters in the MoM, but thought it 
doesn't show up in the books until Half-Blood Prince.  I know that 
Snape's worts memory includes Snape being turned upside down in the air 
by James revealing the gray underpants, but we donn't hear an acutal 
spell there...where is it written in the books?  
~Goodasitgets