Low profile 3.5mm stereo audio jack.
PRT-09536 SparkFun
3.5mm Audio Jack Adapter - RobotShop
Connector Basics - SparkFun Learn
Graphic Equalizer Display Filter - MSGEQ7 - COM-10468 - SparkFun Electronics
Audio Jack - 3.5mm TRRS (SMD) from MindKits New Zealand
PICAXE 18M2+ Microcontroller (18 pin) - COM-10187 - SparkFun Electronics
SparkFun Audio Jack Breakout - PRT-10588 - SparkFun Electronics
Audio Plug - 3.5mm - COM-11143 - SparkFun Electronics
Designing an Audio Amplifier in Real-Time (the Beat Box Amp)
Graphic Equalizer Display Filter - MSGEQ7 - COM-10468 - SparkFun Electronics
SparkFun MP3 Breakout - VS1033D - BOB-10608 - SparkFun Electronics
Surface Transducer - Large - COM-19102 - SparkFun Electronics
Audio Jack Breakout - PRT-08827 - SparkFun Electronics
3.5mm Audio Jack Adapter - RobotShop