According to Major Nelson’s blog, Microsoft will shipping pets for your Xbox Live avatars.
Starting tomorrow you can give your avatar a new companion. Costing 240 Microsoft Points each, you’ll be able to choose from Large Dog, Pug Dog, Dog in Bag, Cat, Siamese Cat, Long Haired Cat, Goldfish, Guinea Pig, Monkey, Bird, Snake and yes….a Pony.
And you can find some examples here.
Source: [ Major Nelson ]