When we pressed him on whether we'd see downloadable anything for the upcoming flood of id Software games coming to the iPhone, he kept his cards a bit closer to his chest, saying it's technically "possible" but nothing's set in stone yet. He also revealed that Resurrection will be getting multiplayer add-ons in the upcoming weeks, so for those of you who already took the $10 plunge, you may want to ask your best buddy to do so as well.
Update: We got some clarification on the DLC from id Software's John Carmack just now, saying, "There won't be any DLC until we have moved the projects to requiring 3.0, and we aren't sure exactly when that will be. Pretty much all of the titles are being set up for DLC in the future. We are prepping the "Spear of Destiny" levels for Wolfenstein 3D classic, and all the various classic games have sequels and mission packs that we can offer. For Resurrection, new content will have to be created from scratch. I expect we will know within a few weeks if the reception to the game is good enough to justify it."