Any radio, be it analogue or digital, with an line level auxillary (aux) in will allow you to play music stored on an i-Phone through the radio.
We have a Tivoli and it works great for this. You just need a 3.5mm to 3.5mm jack cable (anything from £5 to £25), which you then plug one end of into the headphone socket of the i-Phone and the other into the 3.5mm jack on the radio. There will be an input selector on the front of the radio that allows you to select the aux-in.
I like the Tivoli because it's robust and the speaker is of a half decent quality. There is some debate as to whether the analogue signal will indeed be turned off in the next few years. The government would like to do it because it allows them to then sell the airwaves to commercial users. But think of all the car radios that would suddenly become redundant over night.
Plus digital radio signals are less robust and of poorer quality as a result.
It could still happen though.