RivaTuner can be gotten <A HREF="http://www.guru3d.com" target="_new">here.</A> It is a pretty comprehensive o/cing tool. As for the overclocking itself, basically the rule of thumb is to overclock in 5-10MHz increments and when benchmarks start to show artifacts such as "snow", lower it by 10MHz. That way you won't have artifacts and it should keep your card within safe temps.