You can find a variety of companies online to help you with your market research. For example: Sundale Research's (sundaleresearch.com) primary goal is to provide new and mature businesses with objective, accurate industry data and market analysis on a wide range of topics. Their market research is intended to save you time and money while keeping up with industry trends. But your idea may be so new that you may also need to talk to potential customers, host some focus groups, talk to an ad agency, or maybe even make a prototype and float it past some people. Be prepared to spend the time. Remember, it's not about the Plan but the Planning.
As I conclude, I would like to advice all people, who want to start any kind of business or who already have business without a business plan, to think about creating one as way to building a successful business. One of the causes of failure in business is lack of proper planning. Create a business plan if you want to succeed in your online home business!