With modern laptops getting more powerful every year and audio software doing things never thought possible, you may find that your laptop plays more music than both your home stereo and MP3 player combined. In the interest of keeping things simple, you may be plugging your amps and speakers directly into your laptop's 1/8" input jack and it probably sounds "fine." But listen just a little bit closer and you'll hear the constant whine and noise leaking in from your computer's components. You'll also notice that there's a bit more distortion than you'd like, especially if the signal strength is near the maximum. A low-cost, and easy-to-use solution can be found in audio interfaces like the M-Audio Transit USB, Edirol's UA-1EX USB cable audio interface, or the extremely economical Griffin iMic. All of them offer stereo analog inputs and outputs that are far cleaner than the built-in jacks on your laptop. And they all fit comfortably in your pocket.