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/A,  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). It should
be noted  that we have not  audited  any  financial  statements  of the  Company
subsequent to December 31, 2000 or performed any audit procedures  subsequent to
the date of our report.

ARTHUR ANDERSEN LLP

Phoenix, Arizona
April 27, 2001