Archer,
The first thing I would do is clean the machine. Open the case and dig in to the internals using [guide|3332|this guide] and blast everything with compressed air. Once you are sure that everything is nice and clean, re-assemble and be sure that where-ever you place your xbox, it has sufficient ventilation (IE it's not in some small cabinet or on carpet). You may also consider some sort of external cooling fan and/or setting the xbox so it's standing with the CD drive vertical to give more cooling surface area.