According to sources, Ray Maguire of SCEE dropped this while thanking retail for their support as PS3 passed 1m units in the UK:
So looks like ingame XMB may be here for the launch of MGS4, that is if they keep to that, Sony wouldnt go changing release dates would they ?
Personally im not bothered when it comes out, isnt something im really waiting on.
“Our momentum will continue with the introduction of in-game communication in the summer, firmware update 2.4 and the strongest line-up of games through our third party partners and our own studios. I’d personally like to thank our trade and business partners for helping us on the start of the PS3 journey.”
So looks like ingame XMB may be here for the launch of MGS4, that is if they keep to that, Sony wouldnt go changing release dates would they ?

Personally im not bothered when it comes out, isnt something im really waiting on.