The Mrs. Murphy Mysteries is one of my favorite series by Rita Mae Brown and her cat, Sneaky Pie Brown. The series is set in a small town in Virginia. All of the books feature the same set of characters, but they focus on the animals -- crime fighters in their own right who work diligently to help their humans solve mysteries.
I suggest trying to read the books in the order in which they were written and published. It is a little easier to keep up with the characters that way. They are entertaining, but at the same time you have to do a little bit of thinking to work with the two cats and the dog in making things turn out right.