It's big boss if you couldn't tell, looking a bit older than in MGS3, on his hat it says military without borders which would suggest that the next game is set in the same time period as MG1 and 2. So its most likely a remake of one of those games for PS3.
It appears that Raiden will be in the game too! This probably means that there are infact TWO new MGS games. Platforms at the moment are PSP and PS3. Also Raiden looks even more badass now. He has an eyepatch too and spikes coming out of his shoulder. I would post the scans but it's probably not legal/allowed so go look for yourselves.