Ask HN: What if I think I've made something worthwhile?

I've been working on a project for a few months that has actually turned into something that I think might be userul to other people. It's a niche market, but one that I work in and I see the need for this sort of software in my own work. My application is nowhere near finished, but it's in a decent prototype state. My secret fantasy is to turn this into a business-- but I'm a noob, both at programming and certainly in business. Has anyone done this who can give advice on how to start, or things to consider? Or maybe stories of your own successful or unsuccessful first attempts at starting software-related businesses?