Red Orchestra 2: Heroes of Stalingrad now uses Steam Workshop, allowing players to share custom maps and mods. Modders need to have the Red Orchestra 2 SDK, which is accessible (for those who own the game) via the Tools dropdown in their Steam libraries.

Red Orchestra 2's Steam Workshop capabilities went live on Friday, and Tripwire Interactive has a wiki page for those interested in sharing their creations with the world. Check out the info pages for the SDK here and for sharing on Workshop here.