Here are a number of SF-related websites that I would recommend:
The Interplanetary Railroad
The IPRR used to be dedicated to group-written science fiction stories which everyone helped write by adding a few sentences or paragraphs. It was quite fun. I started the site in 1997, but in the spring of 1999 I found I no longer had time to update it regularly, so I left it in the hands of a different webmaster. The site has since become inactive. It now serves as an archive of old stories that were written a few years ago. Some of the articles found here at The Rings of Saturn originally appeared there.
Science Fiction Weekly A wonderful on-line magazine that covers both literary SF and films. The forum of letters from readers is usually interesting. Pardon me for bragging, but they listed my former website, The Interplanetary Railroad, as a Site of the Week.
The Science Fiction & Fantasy Forum at TrekBBS.com
OSC: Mythopoeic Fiction
A singles' website for Latter-day Saints, run by my sister and her husband. If you are unmarried and Mormon, check it out.
Eric D. Snider
A Guide to Flame Warriors
Dark Horizons-Film News and Rumours
The Survivor Home Page
The Church of Jesus Christ of Latter-Day Saints