It already is. The Sea of Monsters is in production right now. It will be out in 2013.
It has not yet been confirmed if the fifth books of the Percy Jackson series will be made into a movie. If it is, it is estimated to come out somewhere in 2015.
The Titan's Curse (third book in the Percy Jackson series) has not been made into a movie as of yet.
I don't think there will be a 6th Percy Jackson movie as there are currently only 5 books in the series; thought Rick Riordan is going to write a secound Camp Half-Blood series so that might be made into a movie.
Technically, yes they have finished making the Percy Jackson and the Olympians series. But the Heroes of Olympus series is out and includes Percy Jackson as well as a bunch of new characters. Percy Jackson lives on!
Percy Jackson
Yes.
Rick Riordan has made an estimated $50 million dollars off of the Percy Jackson series.
If i am correct, that was a side-comment made by the narrator, AKA Percy Jackson
He made the series off a bedtime story for his son.
Percico is the pairing of Percy Jackson and Nico di Angelo in the Percy Jackson and the Olympians series. It is a fan-made relationship and therefore completely fictitious and unrelated to the book series as a whole.
There is no new Percy Jackson book, the series ended with "The Last Olympian." There is, however, going to be a new Camp Half-Blood series which focuses on the subjects of the next great prohecy, which Rachel made.
The only Percy Jackson book to have been made into a movie so far is The Lightning Thief. It is out on DVD.