Cynthia Rylant wrote a wonderful children's book called Dog Heaven. It really helped my kids(and me as well) with the passing of our pets. I had wanted to type in the text for HG but it was kinda long. Anyway, just thought I would pass that along for the next parent or person in mourning. I believe there is also a Cat Heaven.
When i was in first grade (OH MY WORD, that was so long ago... ) one of my friend's cat died. She and her best friend consoled each other with talks of Kitty Heaven, and how they could visit at night in their dreams. I joined in the conversation of Kitty Heaven and Puppy Heaven and Horse Heaven ... and how easy it was to visit. Just one of those things I never forgot ... I remember the tears turning in to laughter and smiles as we talked about what wonderful places they were. It was one of those comforts that stuck with me for 30-some-odd years ...
When Elvis passed away, the Vet gave us Dog Heaven and For Every Dog An Angel. I LOVE the second one!