Plug your iPhone Earphone into a Standard 3-Conductor Jack
Headphone Splitter for Computer, Earphone Adapter for PC Audio & Mic, 3.5mm Female to Dual 3.5mm Male - Walmart.com
Amazon.com: Headphone 3.5mm Splitter Mic Cable for Computer, KOOPAO Headset 3.5mm Female to 2 Dual Male Microphone Audio Stereo Jack Earphones Port to Gaming Speaker PC Adapter : Electronics
Amazon.com: StarTech.com Headset Adapter, Microphone and Headphone Splitter - 3.5mm Male Aux to 3.5mm Female Audio & Mic Combo Jack Y Cable for Laptop / PC (MUYHSMFF) Black : Electronics
Delock Products 65344 Delock Headset Adapter 1 x 3.5 mm 4 pin Stereo jack male > 2 x 3.5 mm 3 pin Stereo jack female (OMTP)