Filed Pursuant to Rule 424(b)(3)
Registration No. 333-107994

(To Prospectus Dated September 30, 2003)


(aggregate principal amount)

Zero Coupon Convertible Subordinated Notes due June 15, 2008 and the Common Stock Issuable
Upon Conversion of the Notes

        This Prospectus Supplement, together with the Prospectus listed above, is to be used by certain holders of the above-referenced securities or by their transferees, pledgees, donees or their successors in connection with the offer and sale of the above referenced securities.

        The table captioned "Selling Securityholders" commencing on page 38 of the Prospectus is hereby amended to reflect the following additions and changes:

  Principal Amount at
Maturity of Notes
Beneficially Owned
That May Be Sold

  Percentage of
Notes Outstanding

  Number of Shares of
Common Stock That
May Be Sold(1)

  Percentage of
Common Stock

Field Holdings, Inc.   $75,000   *   2,230   0.0%

Less than 1%.

Assumes conversion of all of the holder's notes at a conversion price of approximately $33.6277 per share of common stock. However, this conversion price will be subject to adjustment as described under "Description of Notes—Conversion Rights." As a result, the amount of common stock issuable upon conversion of the notes may increase or decrease in the future.

Calculated based on Rule 13d-3(d)(1) of the Exchange Act using 35,901,144 shares of common stock outstanding as of March 31, 2005. In calculating this amount, we treated as outstanding the number of shares of common stock issuable upon conversion of all of that particular holder's notes. However, we did not assume the conversion of any other holder's notes.