For the same work project I required the iPhone render for, I also needed an IP Phone and choose to very quickly model a basic Cisco IP phone I could put a customised screen on (detailing High Definition Voice calls). This model is basically a front view model and it misses some details, such as button prints (numbers, etc.) as well as the cord (maybe first version with a bluetooth receiver? ;-)).
This was again rendered with Cycles for more realisting light and I choose very simple diffuse materials (with some glossy for the buttons mixed in). In the original, the screen part top surface is also more glossy. If you like to have the blender file, please let me know in the comments.