Yes, they will. Sony has confirmed a few more details for the PlayStation 4 leading up to the next big reveal at this year's Electronics Entertainment Expo. The home console will support Blu-ray discs with up to 50GB of storage and a confirmation of cross-game party chat, a feature that will unfortunately never see the light of day on the PlayStation 3. Source: http://www.cinemablend.com/games/PS4-Uses-Blu-ray-Supports-Cross-Game-Party-Chat-52977.html
When you say cross game, do you mean at their dashboard(home)or only game to game(me in one game, you in another) :|
In the conference video you can even see a video of someone playing and with a videochat activated. Also, you can join the game or command the game? https://www.youtube.com/watch?v=4UDHqZKeMZ8 minute 00:26:47 Seems that you can trigger micro and camera independently. Party chat will be there for sure.