Neopets Legends & Letters is the new mobile app that they were debuting at Comic Con. There's no firm release date yet, but they're aiming for Q4 (October - December) of this year.
A new mobile friendly website is coming for Neopets, projected to be released after Legends & Letters.
Another new app is currently in development (no official title yet) that was described as a "Neopian world building" game.