Gah~! It's fucking short for "Yranoitcid Tekcop" which is, obviously, "Pocket Dictionary" backwards. Fourteen year old me was trying to think of an AIM name that was original, memorable, and didn't involve fucking numbers. I saw my sister's pocket dictionary and, well, the rest is history. I started using the name at message boards after that. It was eventually shorted to "Tekcop" since "Yranoitcid" is the easiest thing in the world to type out.
There. The down low on the history of my screen name. No fucking William Shatner!