Is it possible to buy iphone with the bitcoin ?
Of course, but the question is, is it advisable though? For me it's much better to just convert your Bitcoin to Fiat and then just go the nearest Apple store. Less headache, instead of shopping around the web wherein there are just few options right now to buy them with your Bitcoin.
Is apple accepting bitcoin in future for the purchase of Iphone?
It boils down as to what incentives they will get in they start to accepts Bitcoin as payment method. Volatility is one concern of merchants right now so I guess it will take years for Apple to fully accommodate Bitcoin, IMHO.