Creates the Business Improvement District Law. Provides for the establishment of business improvement districts by a municipality by ordinance after petition by property owners, creation of a district plan, notice, and hearings. Provides that a business improvement district may impose district charges on property owners whose real properties are located within the business improvement district. Provides that the board of directors of a business improvement district shall administer or implement activities and improvements specified in the district plan unless the board contracts with a district management association to do so. Contains provisions relating to district plans, formation of a district, district boundaries, terms and renewal of districts, amendment to district plans, governance of the district, reports of the board of directors of a business improvement district, contesting the validity of a business improvement district, district plan, or district charge, dissolution, and legislative purpose. Provides that the Act applies only to municipalities having a population exceeding 500,000. Defines terms. Effective immediately. Senate Committee Amendment No. 1 Corrects a cross-reference.