Clicking Ready to Publish automatically sends an e-mail to the publishers that are assigned to that page informing them that the page is ready to publish. From there, they have the option of logging into the CMS to review the page in order to publish it. If you are a publisher, you can use the e-mails as a reminder to publish.
If you are in charge of lots of pages, it will probably be easier to use a different method. Log into the CMS and click on the Search Pages tab (on the Web Pages tab) where you can have the system ONLY show those pages that have been marked Ready to Publish. That way it will be possible to review all your assigned pages at one time.