Rage's level editor and mod support will be ready at launch, reports PC Gamer. The news was confirmed by id creative director Tim Willits at a recent press event, who said that both features will be available out of the box. "Pull down the console, type 'id studio', then press enter," he said. "Then, bam, there's all the tools we use."
But apparently creating entirely new levels will be a labor of love that might take a while. "Building levels from scratch is more difficult," said Willits, "because we have a layer system in some of the levels. I can foresee somebody modding up Wellspring and adding different characters, giving them different voice-over." Apparently, though, the tools are "built into the engine," so if you have enough time you can create whatever you'd like.
Id wasn't always so confident about mod tools. In 2009 Tim Hollenshead said the team hadn't really talked much about mod support, and stressed how difficult it would be for amateurs and hobbyists to make art for the game. Even as recently as last year, Jason Kim told us there was no "definitive answer" on mod tools.