Jack connectors have become industry standard on many types of consumer level and professional audio equipment. They come in a few shapes and sizes, so it is important to know what you are looking for.
Instrument / Guitar leads use a TS 1/4" Jack, iPod headphones use a stereo TRS 1/8" jack, and balanced mixing console outputs usually require a TRS 1/4" Jack.
There are both mono and stereo versions of jack connectors, know as TS (Tip, Sleeve) and TRS (Tip, Ring, Sleeve) respectively. It is easy to identify the two, with a TS having one black insulation ring on the plug, while a TRS has two.