Treyarch's Josh Olin (JD_2020) has posted on the official PS3 blog that the First Strike DLC will be available for download on March 3rd for the PS3. Recently, the release date for the PC's DLC has been revealed to be the end of March (Source) The release date for the Wii has yet to be announced.
In related news, Activision has formed a new company devoted to creating digital downloads for Call of Duty. The team will be called Beachhead, and have been tasked with creating "best in class digital experience for Call of Duty." Looks like we will see more Black Ops DLC in the future.
For updates, be sure to follow Treyarch's Josh Olin on Twitter (@JD_2020) and David Vonderhaar (@DavidVonderhaar), as well as the Official Call of Duty site and the Official forums for updates from the developers.