Meeko lives in Meeko's Shack West of Morthal and South of Solitude.
 How to get as follower
Find Meeko in the Shack. His owner is dead so you can tell Meeko to follow you.
 Hearthfire DLC
 How to adopt Meeko as a pet for your children
Bring Meeko to your house and the kids will ask if they can keep him.