Exhibit 23 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation of our report, dated February 29, 2000, included in this Form 10-K, into the Company's previously filed Registration Statements Files No. 333-48407, No. 333-48417, No. 333-58747, No. 333-77093, No. 333-77827 and No. 333-94697. Vienna, VA March 9, 2000