They're the same type of pets as the baby panda or cockroach in WoW. Pet Attack is for Conjuror or Necro pets.
In the Splitpaw Sage you can get a little mushroom guy as a reward who I've seen following someone around out in the world at large.
Here's a little info on the PvP setup from Gamespy.com:
Quote:
Unfortunately, we didn't get to see Maj'Dul's most promising feature -- the PvP arena -- in action, but we did get some more info as to how it will work. If you saw the E3 video, then you witnessed how players will be able to assume the forms of various creatures in order to do battle within it. Apparently, when assuming these forms, players' actual adventuring levels won't come into effect, making these sorts of "champion battles" more of a separate game within EQII's nascent PvP system. Players will be able to acquire different champions by several methods: the most common ones will be available from NPC merchants, while others will be quest rewards. The rarest ones, meanwhile, will be dropped by enemies. Of course, players will be able to engage in more conventional PvP matches, using their actual adventuring levels, but we didn't get much info regarding the types of events that will on offer. Our host did tell us that full-on PvP servers were in the works for EQII, however, so all you stone-cold killers out there, take heart.