No offense and this is just my opinion. But if you've done so little research that you have to ask this question, it's probably better that you don't try overclocking.
The easiest overclock is look in your motherboards manual for multiplier jumper settings. and changing it from 4x to 4.5 or 5x. If your system isn't stable after you do this, change it back. Anything else I would not recommend until you have a good idea of whats going on and that would require alot more information than people will be able to post here. Though maybe and hopefully, some others can help you find some of the stuff you'll need to read.
But I would definately recommend that you read some beginners overclocking guides, especially ones geared towards k62 chips, then research your motherboard, then ask any more specific questions here, (as 'how do I overclock' is a dangerous question to ask).
