According to IGN information revealed at this year's TGS on Crisis Core include the details that there are scenes on Zack and Aerith's background together and that Aerith is wearing blue and white in the game.
Be aware though, that according to Advent Children Net IGN has already got some other details on other Square Enix games wrong, so keep an open mind for now :)
Once we have definite confirmation (i.e back up sources on Aerith wearing blue and white, scans or pictures/screenshots, or a trailer perhaps) I'll let you know :)
Source - Advent Children Net, IGN
Linky -
http://ps2.ign.com/articles/734/734361p1.html