Today is the day Governor Spitzer has been waiting for: Peter Kalikow plans to announce that he is resigning as chairman of the board of the Metropolitan Transportation Authority, according to a state official.

It was back in June when Mr. Spitzer, at the time simply the presumptive governor, vowed to replace Mr. Kalikow, a real-estate developer and former owner of the New York Post, even though he really would not have the power to do so. Mr. Kalikow, just reappointed to a six-year term, promised to stay on—at first he said for one or two years or more, then he said until projects he wanted had gotten off the ground, and then he said sometime in the spring.

Which brings us to today, it being early May, three weeks after the Second Avenue Subway groundbreaking. Mr. Kalikow will continue as chairman until Mr. Spitzer names a replacement, which is expected to take another several weeks, according to the state official. The Governor has ruled out giving the post to Elliot (Lee) Sander, who was installed as executive director and chief executive at the beginning of the year, and who Mr. Spitzer’s office had indicated, during the transition, was in line for the chairman position.

The announcement will take place at 10 a.m., in 101 Park Avenue, a building that Mr. Kalikow’s family owns, and which is located just two blocks south of Grand Central Station.