You did not indicate whether you wanted a multi day tour or just a guided day trip and what type of kayaking you were interested in and whether you wanted any instruction along with the tour.
Try Steve Rohrs or Julio Perez with http://www.kayaktraining.com. They are friends of mine and that is their part time business. They offer extended tours and weekend day trips. They have scheduled a two day overnight trip to Janes Island on the 23rd and 24th of June.
Chesapeake Outdoor Adventures has tours of the Eastern Shore. http://www.harriscreekkayak.com/tours.php
as does Adventure Crafters http://www.adventurecrafters.com/index.html
There are also club outings by Chesapeake Paddlers Association http://www.cpakayaker.org that goes out on weekends on day trips. They have group leaders but are not guided tours in the usual sense.