The old days of struggling to overclock your Palm Pre are over. With new kernels and overclocked backed into Preware, the process is just a couple of clicks away. If you're not up on Homebrew Apps and how to get them on your Pre you can start with PreCentral's guide at the link below.
Once you get WebOSQuickInstall going, and you get Preware on your Pre you're all set. A couple of clicks and you'll be overclocking your Pre in no time.
The overclocks are very stable these days, and seem to pose very little risk to your phone. Palm warns against it, but so many people have done it with success that I've been overclocking mine for a long time.
Check out this video to see just how easy it is.