The brand name blue dish soap is the best grease remover ever! The commercials talk about it getting grease off dishes, but it also does a bang-up job of getting it out of cloth or fibers, too. It's a great stain remover.
The accepted wisdom says you should test it on an "inconspicuous area" to make sure it doesn't take the color out, but I've never seen it do that. Still, if you're super picky about your carpet, do the color test. Always good to make sure, I guess.
And there's professional cleaning if you make a hash out of getting the soot up, but I'd try it myself, first. The pros do a good job, but they will walk away with a large chunk of your cash.