REIT Investment Diversification and Empowerment Act of 2006 - Amends Internal Revenue Code provisions relating to real estate investment trusts (REITs) to: (1) treat passive foreign exchange gains attributable to overseas real estate investment as qualifying REIT income; (2) increase from 20 to 25% the the maximum value of a REIT's total assets thay may be represented by securities of one or more taxable REIT subsidiaries; (3) revise safe harbor rules for the excise tax penalty on certain REIT sales activities; (4) treat rental payments made by a health care facility to a REIT as qualifying REIT income; and (5) treat income from, and interests in, foreign-qualified REITs as qualifying REIT income and assets.