Well, they're going to be bringing in the originally announced features for iDisk for starters
(Share files via iDisk, so you effectively "email" them to people (send them a link, they get the file from a part of your iDisk))
Adding some more features seen in Contacts/iCal etc would be good. Looking forward, i'd imagine some of the features will roll out lock step with Snow Leopard (Server)'s features come WWDC 2009.