Project Diva is a rhythm game for the Sony Play Station Portable (PSP). It was only released in Japan. However, it is not region locked meaning it can be played on an American PSP.
If you want to play this game, just make shore that your PSP is one of the models that has a UMD drive. In other words, any PSP that is not the PSP Go right now. Also, as I stated before this is a Japanese title so you will have to import it. You generally won't find it at your local gaming store.
Language barrier is a minor issue as most of the game play is based on matching the buttons to the timing of the music. here is a sample video below of the game play.
http://www.youtube.com/watch?v=cqVMNTTTCCoThe only complicated issue I have had is working with the edit mode where you can create and edit you own videos with your own mp3 files. Sadly, this is a little less language friendly and I'm still working on figuring this mode out myself.
Besides that its a great game and I really enjoy it. (why else would I make a guild around it. lol)