IT workers who've recently been laid off are lining up at staffing agencies in search of temporary and contract IT work that will provide them with a paycheck as they look for full-time, "permanent" IT jobs.

Spokespeople for Technisource and Robert Half Technology report a sizeable increase in inquiries from IT workers over the past three months. They say that unemployed IT professionals and tech workers who are concerned about their job security look to staffing agencies for leads on jobs and to help market themselves to prospective employers. (For more information on the benefits of working for an IT staffing firm, see Why You Should Register with a Staffing Firm.)

IT professionals agree that working for a staffing firm can be an effective way to connect with employers, to broaden their skills and gain new experiences working in different environments. Contract work may seem like a stop-gap for tech workers who've been laid off, while they figure out what to do next.

But working for a staffing firm has serious downsides, too, they say—including drawbacks that down-on-their-luck IT professionals may not consider, to their disadvantage. For example, working for a staffing firm isn't always a quick financial fix: It can take staffing firms a long time to find appropriate work for their contractors (especially in this economy), and IT professionals may not get paid by the firm when they're "on the bench" between client engagements. Moreover, IT professionals who work for staffing agencies may not get a lot—or any—benefits, and whatever benefits they do receive may be docked from their hourly rates. Hired guns can also easily be taken advantage of by less reputable staffing firms and their clients.

"You have to be very, very careful when working with recruiters and staffing firms," says Walter Poe, an SAP systems engineer for The Timken Co., who's gotten temporary and contract work through staffing firms in the past. "Some recruiting companies are more interested in quantity than quality. That's what you have to be looking for. You want a firm that invests in you, that trains you and builds your knowledge because that makes the staffing firm look good."

What follows is advice from seasoned IT professionals who've worked with staffing and consulting firms on what to watch out for and how to avoid difficult situations.