How long does it take? This seemed a worthwhile topic. A lot of mystery surrounds the process for those who haven't been involved in the business side of thing for ages. The answer, as with everything in publishing, it varies. That said, here are some benchmarks.
Short story publication: From sending the story off to the market that eventually buys it to seeing it in print is likely to take a bit over a year on the short end, and as much as three years on the long end. I'd call 18 months pretty typical. When I add in time from the completion of the story I find that it generally takes 3-5 years from written to published. Getting paid can take even longer.
Novel publication with a big New York house: From sending the novel in for consideration to publication again runs between a bit over a year and 3 years. So far, my fastest time on a completed novel is 18 months from submission to publication. My most recent pre-contracted novel is taking 16 months from purchase to publication (including writing it), and 10 months from turning it in to publication.
Those numbers are only for stuff that sold. I've also had a multi-book deal fall apart that took just under 3 years from first book submission to final rejection for it and the 2 I sent in while I was waiting to hear on the first. I've had short stories that were waiting for a response for up to a year before I pulled them from a given market. I've also had several short stories that sold and were paid for that are now back in my submission files because the markets folded in the year or more between acceptance and would-have-been publication.
Anyone else have any data points they want to add?