The Colby alumni directory is scheduled to be released early in March. Alumni who reserved copies should receive their books two to three weeks after release.     The comprehensive new volume is a compilation of the most current data available on more than 19,000 Colby alumni obtained from questionnaires, telephone verification and existing alumni records.     Persons who have questions or who wish to place an order should contact the publisher: Customer Service Department, Bernard C. Harris Publishing Co., Inc., 16 Koger Center, Suite 103, Norfolk, VA. 23502; or call 1-800-877-6554.