This is an idea that came up on the Simple Dollar blog a few days ago and I thought it was really great and I plan to start doing this.
Set up a savings account (online banks like ING Direct are great for this because they have good interest rates) and deposit your earnings into that account. Then set up automatic transfers bi-monthy for a set amount of money and treat that as your paycheck. This makes it easier to grow the savings you may need for your business and provide a cushion for months where you earned less. As your business grows you can adjust the amount to pay yourself more.