As prices rise, incomes stagnate and the pressure gets ever tighter on the middle class, more and more people are starting part-time small businesses to supplement their income and create an escape hatch in case their full-time job disappears.

A growing number of people are underemployed, meaning that they work at part-time jobs or have had their hours cut back at full-time jobs. According to the Bureau of Labor Statistics, nearly 8.8 million people are employed part-time because their hours have been cut back or because they’ve been unable to find full-time work.

Many of the underemployed are turning to part-time work outside their regular jobs to supplement their income and establish a safety net in case they join the nine percent of Americans who are unemployed. Many of these people are starting their own business ventures, contracting their services out online or from home businesses, becoming what’s known as moonpreneurs.

For example, many professionals who are underemployed are turning to freelance work Web sites such as Elance to utilize their skills to earn more income. Moonpreneuring via online work helps part-timers because it often lets them find work that they can fit into their schedules and can complete from the convenience of their own home.

According to a recent survey, nearly 36 percent of people who work online via Elance said they started doing it to supplement their income from their regular jobs.

When becoming a moonpreneur, it’s worthwhile to consider the following:

Start-up costs. Starting your own part-time business may have some costs, including membership fees, equipment costs, materials costs, etc. Make sure starting your own part-time business isn’t going to cost you more than it makes you.

Work/life balance. Be sure not to get so overloaded with work that your family life and social commitments suffer. Overwork will quickly impact the quality of work you can offer, and can be harmful to your health as well.

Building your business. Chances are the going is going to be slow to begin with. Be patient and build your business one satisfied customer at a time. As time goes by and you build up a good professional reputation and a stable of repeat clients, your business will expand.

Time management. Make sure not to overcommit to projects and take on more work than you can possibly complete. Set reasonable completion dates that are accurate for your clients. The best way to avoid overwork and handle your time optimally is to become an expert at planning, scheduling and using your time wisely.

Tax issues. Don’t forget that your other income is taxable too. Be sure to pay the appropriate FICA and income taxes on your moonpreneur income or you may get a visit from the IRS.

Don’t forget your day job. While it’s not providing the income that it used to, your day job is likely responsible for the majority of your income. Don’t let your performance at your regular job slip because of your afterhours work. Also be aware of any non-compete or other clauses that might land you in hot water if you’re caught moonlighting.

Moonpreneuring can help you supplement your income and provide a way to further your professional development. As time goes by and the business grows, you may even want to take it full time at some point. The key to successful moonpreneuring is planning and scheduling, finding an appropriate work/life/work balance and providing quality results to your clients.