Why is Easter associated with bunnies? Are they significant to this holiday?

Rabbits and eggs are both symbols of the fertility goddess Eostre/Easter/Ishtar/Ostara. Her symbol is also the moon, in which some cultures see a rabbit instead of a face. Eggs also symbolize the moon and are the ultimate symbol of creation and new life. The basket is a symbol of the womb in which this new life is carried. There is a lovely legend about the moon goddess Eostre, in which she came upon a dying bird. To save its life, she turned it into a rabbit, her strongest symbol. It lived but continued to lay eggs. In gratitude for its life, the rabbit gives her some of the eggs every year. The feast day is pagan and was widely celebrated way before the time of Jesus. Like pretty much all holidays, it was adopted by Christians to help get more converts. However, since the point is to celebrate new life and the hope of continuance, Christian symbols of a Resurrection day and the old pagan symbols mean the same thing at the heart of it all. Just like Christmas, we are all celebrating the same thing, just using different symbols.

Here is a short article on the history of Easter and it should answer all your questions. It is the first link.