its got skype so you should be able to video chat. What do you mean by video chat during games? That seems like a feature that would take up screen space and make lags. I think that video chat should stay out of games.
Why would someone need video chat during the game? That seems like an information overload since the visuals and motor skills need to be at their peek during that type of competitive video. I do not see how a consistant video chat is needed, anyway.
Will you be able to video chat DURING games? Can't find anything on this. It would be epic to see your friends face after you just sniped him on call of duty.
In Wipout 2048 there is a "brag" shot where it takes a snapshot with the front camera. It might take a lot of server space to host a game and a stream of hundreds of players video shots.
Nothings is out of the realm of possiblity since the Ps Vita is more than capable of handeling multi-tasking functions like voice/text chat while playing games.