So throughout the day bits and pieces of new info have been released/confirmed.

Collections from The Sims 2 Build/Buy Modes finally return

New Sims 3 Pets Expansion InfoNew Sims 3 Pets Expansion Info

Some info from SimGuru Graham

New Sims 3 Pets Expansion InfoNew Sims 3 Pets Expansion Info

Number of Pets and Sims to a household

New Sims 3 Pets Expansion Info

Source: SimFans, SimsVIP and BlackGarden