WiseGEEK is a site that posts informative articles on many different subjects. They sometimes hire writers to help.
However, they may or may not have openings at the time of this writing. I was recently hired so if you apply now, and have a few good writing samples, you probably have a good chance.
On the FAQ page there is an email address you can send your writing samples to. If they are interested, they will get back to you. You might want to check out the website and take note of the writing style they expect. It took about 3-4 days to before I received a response to my application.
The pay is $10 per article, and you get to choose from a pool of available articles. If you are hired, they will give you access to the writing panel where you can choose a "test batch" of 3 articles to write. Once you submit them, they will be reviewed and you will be paid for them even if they don't hire you. So, there's really nothing to lose here. Plus, they paid for my test articles the next day after they were reviewed. That was a nice bonus!
They then asked me to read over the editor's comments on my test articles and submit 3 more. If I am able to incorporate the editor's comments into my new articles I will be "officially" hired. The editor commented that I didn't go into enough depth on a few points. I was writing about herbs, my specialty, and didn't explain what a particular plant was. So, if you decide to write for them, make sure to include explanations of everything you write.
Also, they said I didn't include enough commas. Ha! This was practically beaten out of me by another site I write for (NO SERIAL COMMAS!) so I really had to change my writing style. The great thing about WiseGEEK is that they seem really willing to work with you. The editor's were super nice and the comments were polite and straight forward.
I can't say enough about the positive experience I've had so far with this site. Another plus is that new titles are constantly being added to the pool. Every day I login and find plenty of new titles that I can write easily. They are highly recommended.