i would try Creative Byline. I haven’t used it but I know people who have and have great thins to say about it. They put your work in contact with editors. If you click on the writers link it will show you step by step how it works. Good luck!

I would suggest entering some of the better known contests like Writers of the Future (http://www.writersofthefuture.com). Once you have a few honorable mentions or better under your belt, you will be known by those in the know in the industry. Also go to some of the conventions, especially the larger ones like the World Science Fiction Convention being held in Denver in 2008. A number of sci fi fans like Harlan Ellison have gone onto good careers. Get involved with a local sci fi writers group. The thing is to get out there and let people know you exist. The sci fi community is very accomodating to new writers. The important thing is to think about building a career.

Well, the first thing to do is to learn to write really, really, really well. Most new authors can’t write. Join a writing workshop near you, preferably one that meets weekly.

For your first publication, try fanzines or other on-line magazines. Get some things published. It’s a lot easier to break into the SciFi magazines if you can cite some publications and mention that your work has been workshop-tested.

It also might be worth trying your hand at mainstream writing, unless you have a degree in a science. I’ve seen a lot of SciFi by people who didn’t know any science, and generally it stank. Your work may be a lot better, but mainstream writing pays more, has a bigger market, and can serve as a way of getting your SciFi stories published.

Good luck!

Well, that seems contradictory (how can they be real competitive if they’re not very popular?). The big three are (and have long been) Magazine of Fantasy and Science Fiction, Analog and Asimov’s Science Fiction. And I will say (after a long time of sending stuff out) that science fiction people are BY FAR the most supportive and responsive out there; they’re the only ones who seem to truly care about their contributors (regardless of whether your material is up to snuff).

send it to any publisher you can many are linked to others and may re direct you to that branch of publisher
just keep trying