This the DLC that Microsoft paid a whopping $50million to keep exclusive.
[quote]
“It’s been a long time coming, but we are proud to finally deliver Episodes From Liberty City for the PC and PlayStation 3,” said Sam Houser. “We appreciate the patience of our PlayStation 3 and PC fans worldwide, and we look forward to putting the games in your hands this March.”</blockquote>

The DLC will be available online or on a disc.