Palm recently made it’s webOS kernel source code available for public consumption. Within a few hours the webOS internals team released a custom kernel capable of overclocking the Palm Pre/Pre Plus to 1GHz.
unixpsycho, one of the members of the webOS internals team states in a recent Twitter post that webOS 1.4.5 kernels will now be deprecated in favor of the new 2.1 kernel tree. They will remain available but not be actively maintained. Running the 2.1 kernel requires upgrading your Palm Pre or Pre Plus to webOS 2.1 as part of the process.
The custom kernel release comes with a healthy dose of warning, as these are highly experimental testing kernels. The webOS internals team is hoping to receive constructive feedback regarding any problems encountered to improve their future releases.