All 4 of the packs can be had on Xbox 360, PS3 and PC. They're named the War Hero Pack, the Renegade Pack, the Vegas Pack and the Greaser Pack.
Are they free? HA! They are each priced at $2.99 / 240 MSP on their respective platforms. The DLC packs add new cars or clothing for Vito Scaletta to wear. So far 2 DLC episodes have released for the Mafia sequel with the first being a PS3 exclusive.
The second was Jimmy's Vendetta, releasing for all 3 platforms. A third major DLC episode is being developed and releases this year and it follows Vito's friend Joe Barbaro. Have you picked up Mafia II, videogamer? Are you a sucker for some DLC?