I recommend the Work-at-Home Moms' Forum at http://www.wahm.com/forum/ . They have forums for work-at-home jobs that are legit. Also look on mturk.com and search for requesters like AboutUs Mechanical Turk Operators, Paul Pullen, and Andy K.
There are several work from home jobs that are legitimate. You can find them on the WAHM website or Work At Home Moms. You could also do some babysitting or tutoring.
I found several great job leads at www.wahm.com.
Most of the work at home jobs are not legitimate and will ask you for an up front investment. workathomemoms.about.com/workathomescams is a good website that warns about work at home scams.
The best way to find a successful work at home job is by doing something you already are good at. Services are your best bet, it is much harder to do production of anything at home and make decent money.
You can find guidelines for building a green home at www.nahb.org/gbg. Another good website is www.nahbgreen.org/Guidelines/nahbguidelines.aspx
One can find out if a data entry from home company job is legitimate by calling the contact person listed on the job, checking that the e-mail of the contact person is a business e-mail or by looking on other sources for same job advertisement. Additionally one could check online a 'Legitimate List' with work at home jobs available at About website.
There is a website called WAHM or work at home mom and they offer classified ads with real companies that let you work from home. You could also try babysitting or tutoring.
I would first look at this website called workathome.com. There is this young man that started this website he's really great and he'll tell you about all the legitimate work at home jobs.
Some legitimate home jobs include those that pay you for completing surveys and offers. A great example of this kind of website is treasure troopers.
The best way to find an at home job that is legitimate is to look on the job hunting sites. For example, monster.com and indeed.com both offer online jobs.
The best way to find information about Brinks Home Security is to visit their actual website. Which is www.brinks.com. Their information is very helpful.
Most work from home websites and other schemes are not legitamite. It is hard to find one that is. They either do not pay or ask for money in the forms of fees and other payments.