Unlock in-game T-Shirts:

Enter one of the following codes at the Extras -> Network -> Enter passcode
screen. (you need a PSN account)

Code:.............    Result:

2000016537833....    Big Boss face a la Che shirt (Red)
2000016756791....    Big Boss face a la Che shirt (White)
2000016032758....    Black T-Shirt with Big Boss text
2000016032390....    Black T-Shirt with Peace Walker text
2000016038415....    Black T-Shirt with White Peace Walker Logo
2000016036022....    Gray T-Shirt with Coffee Cup art design
2000016032567....    Gray T-Shirt with MSF logo
2000016032574....    Gray T-Shirt with MSF Logo
2000016032338....    Gray T-Shirt with Snake Art at the Back
2000016032635....    Navy Blue T-Shirt with MSF logo
2000016035902....    Olive T-Shirt with Snake Art
2000016038576....    Plain Tan T-Shirt
2000016032680....    White T-Shirt with Big Boss text
2000016035933....    White UNIQLO T-Shirt (unknown design