Just a quick heads up:
If you're looking for some quality science-fiction, check out Abyss & Apex. They have some pretty awesome FREE stories up on their site.
For all you sci-fi writers, A&A is also a paying market: "US $.05/word (five cents a word) up to 1,500 words, and a flat payment of $75.00 for longer stories".
I submitted a story a few days ago. Keep your fingers crossed for me!