Just to clarify Event Calendar Pro exposes an RSS feed that users could subscribe to with a feed reader like google reader, but it doesn't have a form where users can sign up for notification about events.

You could use the mojoPortal newsletter feature to promote events but there is no automation, the newsletter doesn't know about events, it is just a news letter.

You could also use the included contact form or Form Wizard Pro to capture submissions but there is no automation, you would just receive the data and then would have to follow up manually or some other way to send information about events to the user who submitted the form.

Hope it helps,

Joe