When you reach a level 3 pet (maybe 3-4 battles) you start getting quests to fight NPC trainers. As soon as you beat them you get a follow one quest to fight another NPC trainer. Currently it is looking like one per zone right now (first was in Elywnn, second Westfall and the third one in Redridge).
The first two NPC fights so far have both had two pets each, with the third fight having three. Although these fights arent that hard I dont think it would be doable unless you had a pet of similar level and a backup pet of at least a few levels just to play it safe.
Those who have played or are familiar with Pokemon will understand that a lot of pets have strengths and weaknesses, but the tooltips are all pretty self explanatory anyway for those that havent!
As you can tell Im actually getting really into it at the moment! I did try queueing for a pet battle (just the same as a LFR / LFD queue) but I seemed to get matched with a trainer who had level 12 pets compared to my level 4's so was a bit one sided to say the least! I'm assuming this is either lack of people queueing or the matchmaking isnt fixed yet
Edited by Peelyon, 17 July 2012 - 01:32 PM.