WOW: Pets in Northrend

PET - The Ghostly Skull, available in the sewers for 40G. (The vendor is Darahir, in the northernmost room of the Underbelly)

If you fish, also start casting in the sewers for a Giant Sewer Rat pet. He's random and very rare, and be prepared to use a lure even at max (450) fishing to avoid get-aways.

MOUNTS - Just outside Krasus' Landing (the FP) is Mei Francis. She sells the Armored Brown Bear for 750G, either an Armored Blue Windrider (Horde) or an Armored Snowy Gryphon (Alliance), and the famous Traveler's Tundra Mammoth (which carries two passengers and vendors as well!). She also sells a Wooly Mammoth for 200 Emblems of

Bonus - next to Mei is the entrance to Breanni's shop. Named after the patron saint of pet collectors, Breanni (famous for Warcraftpets.com) sells pet toys - fetch balls, grooming kits, treats and a pet leash.

PETS

The Kalu'ak

These loveable walrus folk in WOW want you to have a penguin, Pengu of your very own (for 12G). The catch is, they want you to do a lot of chores for them first!
They have outposts in Borean Tundra (at Kaskala, on the south coast), Moa'ki Harbor in Dragonblight (on the coast south of Wyrmrest Temple), and Kamagua, on a small island (The Isle of Spears) off the southwest coast of Howling Fjord.

By doing the regular (non-daily) quests in all three towns, you should reach Honored. Once all non-dailies are completed, the only way to get Revered and then Exalted is through dailies. There are three, one in each base, and all are very quick.
The Way To His Heart in Howling Fjord simply requires you to go south, catch some Tasty Fish with the provided net, then lure a walrus bull across a channel to meet his true love. 500 rep, 5 minutes.

Planning For The Future is similarly easy. Just north of Moa'ki Harbor (in Dragonblight) where the quest begins, there are huts with pups to collect. Either kill or CC the nearby Den Mothers, click on and loot each pup, and continue. Collect 12 and return for another quick 500 rep.

Preparing For The Worst at Kaskala in Borean Tundra only needs 8 boxes of supplies, scattered around the village. They spawn pretty quickly, so unless a lot of people are doing the same quest you should also finish this quickly.

If you begin these dailies at 0/12000 Honored, it will take approximately 22 days to reach exalted and get your penguin. (Not counting +rep for humans).

The Oracles

Once you declare your allegiance to the Oracles, you can begin earning rep with them. Once you reach Revered, you can buy a Mysterious Egg for 3G. After seven days, the egg will hatch into something. There is a possibility that you will get a Cobra Hatchling, a Proto-Drake Whelp, a Tickbird Hatchling (brown), or a White Tickbird Hatchling. These pets are NOT BoP, so if you prefer to ally with the Frenzyheart, haunt the AH and prepare to spend! (Note - these do NOT currently show up under pets: you must search 'Cobra,' 'Tickbird,' 'Whelp,' or some permutation thereof to find them!)

You will be at Honored with them after finishing the allegiance chain, so it will only take seven days of doing their dailies (1700/day for the three possible dailies) to get to Revered.

You might also get a MOUNT from this egg, the Green Proto-Drake.