Exhibit 99(b) Certification Pursuant to Section 1350 of Chapter 63 Of Title 18 of the United States Code I, Susan Tomasky, the chief financial officer of American Electric Power Company, Inc. AEP Generating Company AEP Texas Central Company AEP Texas North Company Appalachian Power Company Columbus Southern Power Company Indiana Michigan Power Company Kentucky Power Company Ohio Power Company Public Service Company of Oklahoma Southwestern Electric Power Company (the "Companies"), certify that (i) the Annual Reports of the Companies on Form 10-K for the year ended December 31, 2002 (the "Reports") fully comply with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and (ii) the information contained in the Reports fairly presents, in all material respects, the financial condition and results of operations of the Companies. /s/ Susan Tomasky Susan Tomasky March 20, 2003