Simple publish/unpublish scheduler

I'm trying to put together what I thought would be a simple Rules configuration, but so far no luck stumbling through Rules. Here's what I'm looking to do:

Rule 1: If the date (cck field) is 'now' then 'publish'.
Rule 2: If the date (cck field) is not 'now' then 'unpublish'.

I would like this to be triggered by a cron job.

Can this be easily accomplished?

Many thanks for reading!