Just saw this on Twitter... No one else seems to have this news yet though?
Edit: a Dutch sports magazine's website reports about the deal too.. Source is a Spanish radio channel called Cadena Ser, they say it's a 5 year deal, with an option for a 6th year, that Alonso uses a clause in the Renault contract and that he will earn €25 million per year at Ferrari.
The deal should be announced officially on thursday... Would mean we finally have a true fighter in a Ferrari cockpit again... can't wait!!