Exhibit 23 ---------- CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation by reference of our report dated February 20, 2002 included in this Form 10-K, into previously filed Registration Statement on Form S-8, File No. 33-63671, Form S-8, File No. 333-48081, Form S-8, File No. 333-48882, Form S-3, File No. 333-23157, Form S-3, File No. 333-81913, Form S-3, File No. 333-54704, Form S-4, File No. 333-48293, and Form S-8, File No. 333-68016. /s/ Arthur Andersen, LLP Vienna, Virginia April 1, 2002