Here ya go using Google Feedburner for E- Mail Subscribers

Hi!
If you host you're site here at WA (which I do), you cannot add an rss feed or most things that require an API - a lot of them would/can cause a security threat to the WA server, so Kyle & Carson don't allow it.

I remember trying to do the same thing.

Response from support: "WA does not allow plugins/themes which requires time to time connections to remote servers so all the outgoing connections are blocked by default."

RSS is delivered in a few different formats:
http://example.com/feed/
http://example.com/feed/rss/
http://example.com/feed/rss2/
http://example.com/feed/rdf/
http://example.com/feed/atom/

(provided your permalinks are set)

Wordpress will output these automagically.

You can manually add it to a TEXT sidebar widget via image instructions.

Or, you can use a plug-in.

its usually your domain plus the slug feed i.e.

http://mydomain.com/feed

or go to feedburner and set up a custom feed...its free