If you were recently laid off, or your budget is stretched, or you just need some extra work on the side, you might find yourself checking out one of the major online job/consulting web sites: Elance.com, Guru.com, RentACoder.com or oDesk.com.

Can they really work for you? The answer is… maybe.

Even though all four do focus on technology jobs, there is a surprising variety of work available including writing, graphic and art, marketing and other administrative and service jobs.

All four sites allow clients to post job listings, and freelancers to bid for jobs, usually in an auction style format. They include tools to manage bids and the job process, and a system to manage payment. They also provide various degrees of services to resolve disputes or to escrow funds. Elance and oDesk offer a series of tests that providers can take to demonstrate skills in various areas, giving confidence to clients that a freelancer can do the work, and helping skilled freelancers to promote themselves.

Elance is the oldest of these sites and the most popular. RentACoder, despite its name, also supports non-technical jobs. oDesk focuses on hourly jobs as compared to fixed price projects.

Here’s what you need to know about these sites before you start:

• If you bid on a job, you’ll be competing with people around the world. In fact, you’ll be amazed at how little people in some parts of the world will bid. That’s because a few dollars an hour can work well in a country where the average wage is a couple of hundred dollars a month.
• Many of the projects posted are unrealistic – people asking for a clone of ebay for under $500 for example. What ends up happening in these cases is that usually somebody ends up getting ripped off (either the client or the consultant who underbid or fails to deliver).
• A lot of projects go bad. They get cancelled. Or the consultant who bid on the work never delivered, or delivered poor results. Or the client has unreasonable expectations, or doesn’t actually know what he wants.

So can you get work and make money on these sites?

Yes, but you have to work at it and use care.

• If you take a fixed price project, make sure the scope of the project is very clearly defined ahead of time, and that the client understands that any changes will cost extra.
• Don’t be afraid to bid higher. Smart clients will choose based on qualifications and not just on price. And you really don’t want the stupid clients.
• Take the time to learn how the site works.
• Be patient – at first you may find the number of jobs limited because you don’t yet have a ranking or experience.
• Be more patient – a large number of the projects on all of these sites are unrealistic, poorly defined, or obvious attempts to get something for nothing (or very little). There are good projects – but they’ll take time and diligence to find.

Though the promotional material for all of the sites include testimonials from happy businesses and consultants, the truth is that most of what these sites provide is low cost outsourcing for small and medium size businesses.

For more information: I highly recommend Thomas Friedman’s Book “The World is Flat” as essential reading for those who wish to learn how to survive in the global economy.

A brief comparison of the four sites can be found here.