error_messages helper

i'm resending this, not sure what happen to my last email?

about section 8 in 'Active Record Validations and Callbacks', since
error_messages helper has been refactored out in rails 3, do we want
to move this section out and possibly update it with relevant text
going over how to do it in rails 3

is someone working on this right now? if not i can try to take a stab at it =)