This is a release of the original PC version, but XSEED has added all of the new features in the PSP version back into it, so this is the definitive version of the game in North America. The game was first release for the PC in Japan in 2004 it later received a port to the PSP in 2006 that added some extra features, and the PSP version was released in North American in 2011.
If you're looking for an oldschool, turn-based JRPG with a strong story, great writing, and wonderful music, you will love Trails in the Sky.