After previous rumours that Kingdom Hearts will be featured at the Square-Enix Party 2007, it appears to be becoming less and less likely, although Yoko Shimomura will still be present. Tetsuya Nomura’s “surprise” should still be revealed and may or may not be related to Kingdom Hearts.

The Square-Enix Party 2007 will be this coming weekend (12th & 13th May) and there is now a commercial for it in Japan:



Also, any previous rumours you may have heard about The Last Remnant being possibly related to Kingdom Hearts are FALSE. Confirmed today, The Last Remnant is a completely unrelated game to be released in Spring 2008. If you want to see details:
See the Game*Spark article here