If you're looking for something that will allow you to quit your regular job (if you have one), I'm not sure if any of these would fit the bill, but these are things that I've done from home and was always paid on time:

Write "How-Tos" for eHow:
http://www.ehow.com/write.html

Write technical "How-Tos" for BrightHub:
http://www2.brighthub.com/writers/writers.html

Write on sites like Xomba, HubPages, and Bukisa and earn money through GoogleAdsense. You can also add Amazon and EBay affiliate links to HubPages to more earning potential:
http://www.bukisa.com/info/learn-more
http://www.xomba.com/
http://hubpages.com/faq

If you are a good typist, you can try transcription. I have worked for the following companies from home and was always paid on time:
SpeakWrite: http://www.speak-write.com/TypistNav/Employment/index.cfm
Allegis: http://www.allegisteam.com/WEB/about-us/

Another good source for finding legitimate at-home work is the Work At Home Moms website: http://www.wahm.com/forum/
Check out the forums under "WAHM Service Businesses" to find out about a particular line of work and communicate with other WAHMs that work for these companies. I found most of my job leads here under the "Transcription Services" and "Wahms Who Write" forums.

If you want to find out about more writing sites, check out this site:
http://freelancehomewriter.blogspot.com/search/label/Upfront%20Pay%20Sites

What you want to look out for are work-at-home jobs that want you to pay for the information. A legitimate at-home job isn't going to ask for money from you. The only job I had to spend any money on was the transciption jobs, and that only becuase I had to buy a USB foot pedal to do digital transcription, and that's about an $80 investment - and you can write that off as a business expense when you do your taxes.

Good Luck!

You could try using Mahalo. http://www.mahalo.com/

This question comes up repeatedly. My answer is that there are no at home jobs in our society. In theory you could be a writer or poet or artist or even some sorts of craftsman. But if you had one of those talents and training you wouldn't be asking the question. If you are unskilled you will have to go to a workplace and learn to use their equipment and procedures to do useful, paid work. If you have a skill you already know if it can be done at home or not.