Science Fiction is often muddled into the same category as Fantasy because the two have similar plot structures: society in need of a revolution as the result of a dark and terrible tyrant leader, the end of the world or some other catastrophic event that threatens the universe as the characters know it. Sci-fi as a literary, film and television genre differs from Fantasy in that the parallel driving forces of sci-fi are technology and/or new creatures categorized as extra-terrestrials while Fantasy is driven not by significant scientific or technological elements, but supernatural, magical elements which create new worlds and creatures.

One of the devices of Sci-fi that sets it into it’s own genre is the element of otherworld-ness. Fantasy environment settings are often semi-plausible, originating from something that we already know, such as a new world accessible through a wardrobe (The Lion the Witch and the Wardrobe). Sci-fi tends to exist in space with new planets and new people from those worlds: extra-terrestrials (ET). In addition to these new organic creatures, there is also an element of human + technological integrative development, involving robots, cyborgs and machines (A Space Odyssey), most often performing functions that are entirely impossible, such as teleportation (Star Trek). Relationships concerning human and non-human can often be a driving force for the plot, or perhaps a way of speaking on humanity (I, Robot). Also, things that do not normally have voice can be given voices and personalities, such as dogs, houses etc (Hitchhiker’s Guide to the Galaxy). The farthest reaching convention of sci-fi is the convention of beating the system, or breaking rules. There is some sort of hierarchy that leaves people underprivileged and/or oppressed; revolution comes and births a work of science fiction (Star Wars: A New Hope). Sci-Fi films (and television) are known for being dated by the quality of special effects that are inherent in Sci-Fi films due to their creative nature. Some other topics of interest in writers and screenwriters of the twentieth century are nanotechnology, biotechnology, time travel, space travel and mutant humans. 

For our purposes, we will be referring to the development of sci-fi as the last 100 years, with the exceptions of Carl Sagan and Isaac Asimov. There are traces of Fantasy and Sci-Fi in writing much older than the twentieth century, but Sci-Fi really started exploding as it's own culture in the twentieth century. 

A comprehensive sci-fi film site:  

http://www.filmsite.org/sci-fifilms.html

A sci-fi author online magazine: 

http://www.strangehorizons.com/

A recommended reading list for feminist sci-fi readers:

http://www.magicdragon.com/UltimateSF/thisthat.html#feminist 

The SciFi television channel resource for all things sci-fi:

http://scifiwire.com/index.php