Buy a real of cat5 or 6, a kit for crimping rj45 plugs, and a bag of plugs and covers.
Download the simple wiring diagram from Maplins and you're good to go.

I've made various lengths for several bits of kit including sending wis up into the loft and then down into bedrooms. Works a treat.

Really not too hard. No soldering.


Rgds,
Nick