Future publishing is a standard feature in eZ publish. You need to add a datetime attribute to your class(es), create a new workflow with a Wait until date event and add this workflow to a trigger. Make sure you run the runcronjobs.php as a cronjob aswell.
Currently we dont have an unpublish feature, but we are working on it for 3.5. Have a look at the spec here: http://www.ez.no/community/specs/hide_unpublish
On order to add to the community knowledge:
This worked fine for me (for timed publishing). Using a 3.4.4. installation, i created a copy of the article class, added a "datetime" attribute for this.
Then i create a new workflow with the "wait until date" event, selected my new class and that new attribute. After saving the class, i assigned this new workflow to the "before publish" trigger.
That did the job! Remember, that you need to set up a cronjob for the workflow to "advance". See http://ez.no/ez_publish/documentation/installation/the_cronjob_script for cronjob information.