TPS problem

[luchoadrian]

Hello,
Last week the "check engine" light lit up in my 1998 mitsubishi mirage DS. I was concerned so I took it to a couple of auto zones (just to be sure) so they can check it, what they told me is that the Throttle Position Sensor (TPS) needed to be changed. I would like to change it myself, but I would like to know if it's difficult to do so, and some info (preferible an image) on where is the sensor located, and the position it needs to be put in.
Thanks so much in advance...