I second fostering--it also allows you to get to know the animals in question really well. The shelter I work with has 'cleared' me to adopt any of the animals I foster if I am so inclined (I have no plans to at the moment).

But this has also given me the time to know that certain kittens, no matter how cute they look are incredibly needy & annoying. Fostering would give a family time to decide if the animal is right for them before adopting--and give kids the idea of how much work it takes to care for an animal on an extended basis.