This was a response from James Thorpe of Sony from a question pitted to him by user ADMAN111 in the comments section on the post PlayStation 3 Firmware (v3.10)
The full conversation exchange was;

ADMAN111
When is there going to be Cross-Game voice chat? You can’t hide it forever.

James Thorpe
I wish I could just give you a date, I really do!! Trust me when I say that as soon as I hear from ‘up top’ I will be shouting about it and making myself the most popular person on the blog 😉

James Thrope’s response was vague at best but it does at least confirm that something is in the works and that he will pass on the information when possible.