Just like Fallout 3 before it, Fallout: New Vegas is slated to get a number of downloadable add-ons. The first one, Dead Money, was released on Xbox Live on December 21st.

The Dead Money add-on delved into the mysterious circumstances that surround the Sierra Madre Casino. It raised the level cap from 20 to 35 and added new achievements, perks, enemies, and more.

Dead Money was released as an Xbox 360 exclusive but it is expected to eventually be released on PS3 and Xbox 360. Bethesda has chosen to remain coy about it, however.

“I think we’ll probably just have to wait and see," Bethesda's Pete Hines told VG247. "I wouldn’t want to say anything more than that. Right now, it’s exclusive to 360. That’s the only place you can get it. I’m not going to comment on other platforms.”
It's a different story when it comes to further add-ons, however. Hines has stated that 2011 will definitely see more Fallout: New Vegas DLC being released.

"Oh, absolutely. I don’t think we’ve ever had a product where we said, ‘Yeah, we’re just gonna do one DLC pack and that’s all she wrote,’" he said. "We like to support our products. We like to do a good job of that, and I don’t think putting out one DLC pack would reach that.

“I would say you can probably look for other stuff from us down the road."

Exactly what these add-ons -- and whether or not they'll be exclusive to the Xbox 360 again -- have yet to be revealed, but that hasn't stopped Fallout fans from cooking up their own theories.
The Fallout wiki postulates that the next DLC pack will be Honest Hearts, so named after files that bear the name "nvgraffitihonesthearts" found in New Vegas' "nvdlcgraffiti" folder. This theory gained even more merit after Bethesda's parent company, ZeniMax, trademarked the name "Honest Hearts".

Two more possible DLC packs are Old World Blues and Lonesome Road. There is no additional info on the former yet, but the latter is expected to delve further into the mystery between the Courier and that other wasteland messenger who was supposed to deliver the platinum chip. If you'll remember, Johnson Nash tells the Courier this story when asked about the delivery job.

Perhaps it will also tie into the mysterious wreckage near Mojave Outpost that bears grafitti telling Courier Six to go home, seeing as how the words "Lonesome Road" appear there.