She was at Politics and Prose today with her father Jules Feiffer, and will be in Old Town Alexandria tomorrow. See "Big Woof: Kate Feiffer's 'Which Puppy?'," by Express contributor Stephen M. Deusner, Express April 30, 2009.
Also as we've noted, they'll be appearing tomorrow:
We’d be thrilled if you would mention that Jules & Kate Feiffer will be appearing at Hooray For Books! 1555 King St., Alexandria, VA on Friday, May 1 at 7 p.m. We’ll have copies of “The Explainers” and “Great Comic Book Heroes” on hand.