Exhibit 23

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

As independent public accountants, we hereby consent to the incorporation of our
report  dated March 14,  2001,  included in this Form 10-K,  into the  Company's
previously  filed  Registration  Statements  on Forms S-3 (File Nos.  333-14539,
333-71541,  333-91279,  333-91433,  333-94099,  333-94731 and 333-41498), and on
Forms S-8 (File Nos. 333-50881, 333-71543, 333-92799 and 333-92807).

/s/ ARTHUR ANDERSEN LLP

Phoenix, Arizona,
March 28, 2001