Apple today quietly kicked off a new promotion that offers customers who purchase a Power Mac G4 800MHz a US$200 mail-in rebate and those who purchase a 933MHz or dual-1GHz configuration receive a $300 mail-in rebate. No additional purchase is necessary and the promotion may be combined with Apple’s other promotions, including its Power Mac and Display promotion. Details of the offer, as well as the rebate, will be made available on the Web on Monday; purchases made from today through July 7 are eligible.