ESRB has rated a bunch of new PS2 and PS1 Classic releases for the Sony Entertainment Network Store. The most notable one is Dead or Alive 2 Hardcore. The fighting game came out first in Japanese arcades in 1999 before being ported to the Dreamcast and PlayStation 2 in 2000. The Hardcore version adds several new stages, gameplay improvements and other enhancements compared to the vanilla release.
The other PS2 Classics that were mentioned are Alter Echo, Disney/Pixar Cars, Legend of Kay and MX vs ATV: Untamed. These downloadable releases of these games, along with Dead or Alive 2 Hardcore, is only compatible with the PlayStation 3.
Last but not least is Battle Hunter, a tactical role-playing game. As a PS1 Classic, it can be played on the PSP and Vita along with the PS3.
All above-mentioned games are being published by Sony Computer Entertainment America and should be arriving on the Sony Entertainment Network Store in the near future.