Jed Lewison at DailyKOS put together this excellent takedown of McCain's ongoing stream of lies and misrepresentations of Obama's proposed tax plan.  To summarize, no-one with a taxable income of under $250,000 will see an increase, and will in fact get a tax cut.  Taxpayers in the $250,000+ brackets will see a modest increase, as the tax brackets are returned to those in force before the Bush tax cuts (which favored the wealthiest Americans).