Supposedly "hundreds of titles."

http://www.neogaf.com/forum/showthread.php?t=819094

I was assuming it would be mostly first party PS3 games and some of the previously available PSOne Classics, but if it's really hundreds, well, that's a lot of games. It's also rumored Sony will unveil new PS1 and PS2 emulators with improved upscaling to help older games fit more naturally on modern TVs:

http://www.eurogamer.net/articles/di...heading-to-ps4