This excerpt taken from the AAPL DEF 14A filed Apr 16, 2007.
Shares Available for Issuance. A cumulative total of 1,600,000 shares of Common Stock may be delivered pursuant to awards granted under the Director Plan. As of March 1, 2007, 420,000 shares remained available for future award grants under the Director Plan. If an option lapses, expires or is otherwise terminated without the issuance of shares, the shares underlying the lapsed, expired or terminated option or the tendered shares will be available for future award grants under the Director Plan. However, if shareholders approve the Director Plan proposal, shares that are exchanged by a director or withheld by the Company to pay the exercise price of an option granted under the plan, as well as any shares exchanged or withheld to satisfy the tax withholding obligations related to an option, will not be available for subsequent awards under the Director Plan. Either authorized and unissued shares of Common Stock or treasury shares will be issued under the Director Plan.