Small Business Tax Simplification Act - Amends the Internal Revenue Code to exempt certain small business taxpayers from the requirements of using the accrual method of accounting and of using inventories. Allows such taxpayers to use a cash method of accounting if they meet the gross receipts test and are not engaged in farming as a corporation. Increases the amount of the gross receipts test to $10 million (currently, $5 million) and permits an annual inflation adjustment of that amount.