via mugglenet:

As we first reported the other day, Warner Brothers and Universal have announced plans to build a Harry Potter theme park in Universal Studios Florida. The Sun Sentinel is now reporting that the whole project will cost between $230 and $265 million:
Universal intends to spend $230 million to $265 million to create "The Wizarding World of Harry Potter" at Islands of Adventure along with a previously announced Simpsons attraction, according to a filing Thursday with the Securities and Exchange Commission.

This year alone, the expenditure is expected to reach from $75 million to $85 million, the filing said.
The article includes some more details on the deal as well. Universal must pay Warner Brothers undisclosed licensing fees and the current deal lasts for 10 years (with two optional 5-year extensions).