Slack has a great interface, easy setup, and you'll see StatusPage.io on the list of services that they integrate with.

First, you'll need to activate the StatusPage.io service.

Copy the Webhook key.

Once your key has been copied, head over to the ChatOps section of the nav bar of StatusPage. Paste your webhook URL and then add your channels one by one.

Note: You'll need to make sure you have the ChatOps Add-On enabled.