This excerpt taken from the GPS 8-K filed Nov 16, 2006.
RECONCILIATION OF FREE CASH FLOW TO GAAP FINANCIAL MEASURES
Free cash flow is a non-GAAP financial measure. We believe free cash flow is an important metric, as it represents a measure of how much cash a company has available after the deduction of capital expenditures, as we require regular capital expenditures to build and maintain stores and purchase new equipment to keep the business growing. We use this metric internally, as we believe our sustained ability to increase free cash flow is an important driver of value creation.