If the headphone jack, mute switch, or volume buttons are causing you problems on your Verizon or Sprint iPhone 4, a DIY repair can most likely get you back in working order again for a lot less than the cost of a new iPhone. As it happens, one component controls all of these functions so regardless which is misbehaving, this one guide should get you all fixed up again.
This particular repair isn't the easiest in the world but will definitely be doable for the intermediate to advanced DIY ninja. If that sounds like you, follow along...