Square Enix has stated that both Final Fantasy X HD and Final Fantasy X-2 HD will have saves that can be shared between the PS3 and PS Vita versions of the games.
It was announced in the past that if you buy the game on PS3, you'll get both X and X-2 in the package, but on the PS Vita, these will come as separate titles. However, this is great news for those who want to continue their adventures on the go.
The news was revealed by Yoshinori Kitase, who's currently in France for Japan Expo 2013. It was also revealed during this time (via Japan, not Japan Expo) that there would be an additional 30 minute ending sequence included in the bundle. It's been penned by Kazushige Nojima and it will feature newly recorded dialogue.
There's no concrete release date yet for the Final Fantasy X/X-2 HD Collection, but it should be releasing later this year on both the PS3 and PS Vita.
Source: RPG Site