Quote from Vrumm:
Does the new MacBook White Unibody "use the 64-bit kernel" ???
Apple should atualize this list: http://support.apple.com/kb/HT3770
i've got a unibody macbook (before they turned them into pro's) and unfortunately Apple lock the MacBook's in to the 32-bit kernel (at time of writing), the Pro model's get the 64-bit mode enabled. I'll post a guide on how I got around this on my blog later www.red91.com
Annoying they've done that though, personally like the option of replacing my battery, the previous one went thru 3!