I found a couple of links with new rumors regarding GTA Online Heists. As is normal protocol, take these with a lot more than a grain of salt until some of the more mainstream sites start talking about them - especially the release date:
Rumors of Feb 24th release date. Also, info about other DLC Online missions here.
Apparently, there was a listing on the PS Store that Heists are coming out on Feb 24th. Also, the link above has info on some features in the Heists DLC.
Another link with the rumored 2/24 date, and some other missions besides Heists
Looks like there are hostage rescues, jail breaks, and weapons dealings (exchange for someone you capture) coming. Another interesting quote regarding Heists:
Among those DomisLive found out were a code for “SET_TSUNAMI_ENV” and “SET_AVALANCHE_ENV.” The two codes were said to bring elements that could affect the heist missions and make the game more exciting for the players.
So, looks like there may be some major weather effects that affect Heists. Interesting.
Looks like a major release, and even though the 2/24 date is sketchy at this point, a consensus seems to be that Heists will release before the PC edition does on March 24th.