Your car should have Bluetooth installed, so phone sorted. Check your communications options in idrive.
I think there is s USB port in the in the storage area under the arm rest
If not, there are small radio transmitters that you can connect to most versions of iPod iphone. These are real cheap and simple to use
There is also a BMW module that can connect the iPod through the idrive. If the module is not already installed in your car the this is the most expensive option.
The module will cost about £200 ist, unless you know someone that can code the module for you, BMW will charge royaly for the honour.