http://www.nicovideo.jp/watch/1271049752 Well, it looks like "Po Pi Po" in Project Diva 2nd is confirmed (0:15 - 0:35); and so is "Sound" (0:49 - 1:29). And air guitaring Miku 0:59!
It also looks like there's going to be Project Diva Arcade coming this summer.
http://miku.sega.jp/arcade/ It's looking like a prettier version of the PSP games. I really wish it would come out on home console, though. Primarily because I know I won't be seeing it here in the US. If any arcade would get it locally, it'd probably Arcade Infinity, but I really don't want to have to go all the way down there. Anyway, to save your progress, it's using an IC Card which you pretty much scan/tap with the machine. And also better character models since it's not limited by the PSP hardware, which is why even more I want it to come out on home console. Here's hoping that it does well enough, and a home release will be announced sooner rather than later.