Pediatric Workforce Investment Act - Directs the Secretary of Health and Human Services (HHS), acting through the Administrator of the Health Resources and Services Administration, to establish and carry out a pediatric specialty loan repayment program under which a qualified physician agrees to be employed full-time for not less than two years in providing pediatric medical subspecialty, surgical specialty, or psychiatric subspecialty care in a shortage area in exchange for repayment of educational loans. Requires an area to be determined to be a shortage area based on: (1) waiting times for patient care; (2) recruitment for unfilled positions; or (3) the ratio of the number of children who reside in the area who are in need of such pediatric subspecialty care to the number of pediatric subspecialists furnishing such services within 100 miles of the area.