By Caroline M.L. Potter, Yahoo! HotJobs

Even if you have a job, you may be in the market for another one.

Your current employer may be in dire straits, or you may simply be seeking new challenges. But in a challenging economy, there are a lot of eager professionals gunning for any position -- including your present one. And because most employment is at-will, you may be fired for looking for a new job.

Use these tips to alert your network about your job search without alarming your employer.

Don't Go into Broadcast Mode

Even though you want your network to know you're looking for work, Liz Ryan, founder of AskLizRyan.com and author of Happy About Online Networking: The Virtual-ly Simple Way to Build Professional Relationships, urges job seekers not to use LinkedIn, Facebook or Twitter to indicate that you're job hunting.

The same goes for mass emails. "People process information differently and they may think they're being helpful by forwarding a message when, in fact, they're being indiscreet," she says. Someone could reach out, inadvertently, to someone connected to your boss and blow your cover.

"Remember, too, that gossip is a valuable currency today," she says. If news of your search falls into too many hands, you cannot control how it is spread. "You can't put such a currency in people's hands and expect them not to spend it," she notes.

If you ask for a helping hand, ask your associates to run possible leads and introductions by you before pursuing them. The same goes for recruiters. You don't want anyone acting on your behalf without your approval, as you risk exposing your search to your current employer.

Stay Top of Mind All the Time

Because your network is your most powerful resource for finding another job, you must make sure everyone in it understands what you do and what types of opportunities you're pursuing. "The best possible thing you can do for a search is enroll your job-search army," says Ryan, a former human resources executive. "Meet with them. Talk with them. Ask about their lives. Find out how you can help them. This will get them thinking about you in an up-to-date way."

And if your network isn't big enough, she says that growing it is easiest when you have a job. "Employed job seekers have a huge advantage over unemployed people because they can reach out to anyone in their industry, invite them to coffee and get to know them without asking for anything," Ryan says. These people may not respond to you when you're unemployed. The same is true for those already in your network.

"If you let a connection lapse, you may encounter apathy when you ask for help," Ryan adds.

Be Ready with References

If you're looking for a job while you have one, you probably don't want to use your boss or a current colleague as a reference. This is particularly vexing if you've held the same position for a number of years. "We have to cultivate references all the time," says Ryan, an expert on the new millennium workplace. "Look to people who have left the company, former clients, even vendors. You may think a vendor wouldn't roll over on a client they serve, but they're pragmatic. You may be a good contact for them down the road." Individuals you know through volunteer activities and professional associations can also act as references.

Another great opportunity for references from your current boss and coworkers are LinkedIn endorsements. Ryan suggests approaching your boss in an "up" moment, when you've gone the extra mile or saved something, and ask, "Do you use LinkedIn? May I ask you for an endorsement? It would be fantastic because I'm thinking of becoming an officer in a professional association." Once you have the endorsement, it's there for potential employers to see.