If you've ever wondered if someone made a guitar cable that you could plug directly into a computer, the GuitarLink from Alesis does exactly that. It's about as straight-forward and simple as you could imagine a guitar-to-computer interface could be. One end of the GuitarLink has a standard 1/4" connector that you plug into the output of a guitar, bass, or any line level device (digital pianos, guitar tuners, effect pedals, etc.). The other end of GuitarLink features a standard USB connector that you plug directly into your computer.
You don't have to load any special drivers to get GuitarLink to work, because it will simply plug-and-play with both Windows and Mac computers. It's compatible with any audio software that accepts USB interfaces, such as Audacity (which is available as a free download).
If you're curious about using a computer with your instrument, but not interested in the complex and expensive world of computer audio hardware, then the Alesis GuitarLink is the easy solution you're looking for.