The Bethesda Blog announces the Courier’s Stash and Gun Runners' Arsenal DLC for Fallout New Vegas are both now available, offering one final preview of the new content these add to Obsidian's action/RPG sequel. They are both available on Steam, where they offer these descriptions:

Gun Runners' Arsenal™ includes new weapons, weapon mods, ammo types and recipes. The Gun Runners inventory doesn’t come without a price, though. Trek far and wide throughout the Mojave Wasteland in search of this elite class of weapons that range from the outrageously potent to the bizarrely impractical.

Courier’s Stash™ gives players immediate access to four content bundles previously available only through pre-ordering Fallout: New Vegas®: the Caravan Pack, Classic Pack, Mercenary Pack, and Tribal Pack.