A college degree is also useful for establishing yourself and your credentials in the eyes of outsiders. If you ever want to get investment money or a loan, a number of financial institutions think of an undergraduate degree as a sort of filter, like a union card. If you don't have one, you might need to prove yourself in other ways. I know several entrepreneurs who dropped out of college and now wish they hadn't.
However, if you are in a position of extreme hardship -- one in which you can't continue with your education for reasons beyond your control -- then let it be, and do what you can. But if you can finish your college education at a later time, I suggest that you do.
Education is about you, in most cases, not just about your business. Take advantage of the opportunity. You'll regret it forever if you don't.
Related: The Top Schools for Entrepreneurs
Tim Berry is the chairman of Eugene, Ore.-Palo Alto Software, which produces business-planning software. He founded Bplans.com and wrote The Plan-As-You-Go Business Plan, published by Entrepreneur Press. Berry is also a co-founder of HavePresence.com, a leader in a local angel-investment group and a judge of international business-plan competitions.