Prepare All Kids Act of 2007 - Amends the Omnibus Budget Reconciliation Act of 1981 to direct the Secretary of Health and Human Services to establish a Prekindergarten Incentive Fund from which matching grants shall be awarded to states and, through them, subgrants to qualified prekindergarten providers to establish, expand, or enhance voluntary high quality full-day prekindergarten programs serving children ages three through five.

Requires prekindergarten providers to target children from families with incomes at or below 200% of the poverty line and provide them with program services free of charge.

Directs state grantees to set aside: (1) at least 10% of a grant for quality early childhood development programs for children ages zero through three; and (2) at least 10% of a grant to extend the hours of early childhood programs to create extended day and year programs.