But have your talking points ready if the subject comes up, Frankel says. Point out that "this doesn't take up one minute of my time at work," she says. You can also put it in the context of "I'm doing this to make ends meet." Stress that you're not conducting your business from the office and it doesn't detract from your responsibilities or your ability to put in overtime when needed.
Not everyone agrees. "I would be upfront and present my case," says Janet Christy, who wrote "Capitalizing on Being Woman Owned." "It would be worse if they found out by accident."
Whether you tell, play offense instead of defense: Come in early; stay late; be visible and productive; be prepared and contribute in meetings; take on new projects; and don't be shy about your work-related accomplishments. And, whether you've told the boss or not, never mention the side business.
"You have more to prove than somebody who doesn't have a side business, especially initially," says Christy.
If you're still undecided about informing your boss, look at the corporate culture for budding entrepreneurs, says Myers. Is it openly encouraged? Quietly tolerated? Or tacitly reviled?
Check the personnel manual, says Harper. Read the fine print to see if it covers your situation, he says. And decide, realistically, if your sideline is truly a business, says Christy. "Having a hobby and making some money at it is not being in business," she says.
Going incognitoAny business needs to make a name for itself, and these days budding entrepreneurs want to go global and viral -- using everything from online Web stores to Facebook and Twitter.
But what are the rules when you're still someone else's employee?
Leave co-workers, office friends and clients off your marketing, e-mailing and social networking lists, says Bolles.
If your employer doesn't know or you simply want to keep your two lives separate, consider adopting a business or fictitious name. That way, every marketing tool you use won't be a reminder of your double life.
At the same time, be realistic about your concerns. "You can't be afraid that the boss of your main job is going to find out," says Bolles. "If you live in that kind of fear, you shouldn't be an entrepreneur."
Special circumstancesOf paramount importance: If there's the slightest possibility your business could be seen by your employer as competition, seek legal counsel before you launch, says Harper. "This is a legal minefield."
Even if you're going to be leaving your employer before you launch your business, you don't want to open yourself up to a lawsuit down the road. It pays to get some advice and do everything right from the beginning, he says.
But also consider if your side business is in an area that your company would like to outsource, you could propose starting your side business with your employer as your first client, says Harper. Depending on your needs and how you structure the arrangement, you may even be able to stay on as an employee, he says.
Or, as your business grows, you may be able to work out a part-time arrangement where you work three or four days a week, are accessible to the office on your days off, and maintain health benefits and 75 percent to 80 percent of your salary, he says.
But those deals won't work for everyone. Says Harper, "The more valuable you are to the business, the more your employer might be willing to do this."
Create a news alert for "small business"