Science fiction is my favorite genre, and I'm always interested in new ways to find good stories. A friend pointed me toward Escape Pod not long ago.
Escape Pod brings short-form science fiction stories to a weekly podcast format. Some stories are published first on the podcast, but more often they've been published in an anthology or magazine previously. There's a wide range of both story authors and voices doing the reading. They have an impressive backlog of over 500 episodes (of which I've only listened to 20 or so thus far). None of the stories are very long, generally 20-40 minutes read time.
I generally prefer reading over audio for my consumption of the written word, but there are certainly times when having an audio version is preferable. For instance - making a fairly long-distance drive, or getting some work in on the elliptical machine, or washing dishes. The short stories on Escape Pod fill in those bits of otherwise boring time nicely.
Escape Pod is part of the Escape Artists organization, which also has two other short story podcasts: Psuedopod for horror, and PodCastle for fantasy. I haven't checked out either - plenty to keep me in stories with the sci-fi - but it's cool that they're working with multiple genres. Worth checking out if you like any of those genres and have some time to fill!