Generally - there is no different treatment based on the gross income.
You may find the complete code of federal regulation here - http://www.irs.gov/businesses/small/article/0,,id=108347,00.html
Accounting and record keeping requirements are the same.
However - there are some differences - for instance - the IRS in Revenue Procedure 2000-22 states that qualifying taxpayers with $1 million or less in average annual gross receipts are not required to use the accrual method of accounting for inventories. - http://www.unclefed.com/ForTaxProfs/irs-drop/2000/rp-00-22.pdf
There are some tax advantages available for small business based on gross revenue - for instance - under ARRA, qualifying businesses can continue to expense up to $250,000 of section 179 property for tax years beginning in 2009. The $250,000 amount provided under the new law is reduced if the cost of all section 179 property placed in service by the taxpayer during the tax year exceeds $800,000.
In additional - you might expect greater possibility of audit than someone let's say with $50,000 of gross income.
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Personal Investment, Tax Preparation