Sure enough, there's a new tracking feature for "Wild Battle Pets" that's available on your mini-map. If you can't tell from the screenshot, it's an orange bunny icon.
In the case of the screenshot above, I was standing next to the new Black Sheep critter in Elwynn Forest. This critter also happens to have the new crosshair cursor, so it's looking more and more like the new cursor icon is indeed related to Pet Battles and wild pet collecting! How exciting!
So now I'm making it my mission to scan over all zones in the beta to see if there are more possible wild pets that are in the works. The lovely people over at Petopia's thread have already found a couple new critters: Polly and the Tiny Bog Beast.
UPDATE: Tiny Harvesters in Westfall. :)
Although a lot of the critters are showing up as Wild Battle Pets, we still don't know if we'll be able to collect these wild babies or not. They may simply be critters that our current companions can battle against to gain levels from. We'll have to wait for Blizzard to fully implement Pet Battles and wild pets to find out more.
UPDATE #2: Doobjanka has created a large list of all the critters that he's discovered on the Eastern Kingdoms continent so far. Kalmidor currently doesn't have any of its critters flagged as a Wild Battle Pet yet.