The short answer is, yes. I am doing this on my RX 350. There are two ways to do it. One is to connect the iPhone to the RX USB adapter located in the glovebox near the power adapters (remove the glovebox insert to access). This will allow you to access the iPhone music library through the Enform interface using the mouse.
That said, you can also connect your iPhone 4 wirelessly using the A2DP Bluetooth profile. However, when you connect wirelessly, you control the music through the iPhone 4 interface, rather than the Enform interface.
Hope that makes sense.