Just as unexpectedly as Google turned off support for RSS Feeds of Alerts when they put an end to their Google Reader back in June, today it appears that they have turned them back on.
The Bundle Post has already tested the RSS Feed Channel function and they are working within the system. So for now, it appears that Google Alerts has turned back on RSS support for Alerts.
Login to your Google Alert account. Either create a new Alert and select the Feed option under the “Deliver To:” drop down, -or- go to your Manage Alerts page and edit a specific alert to change the Deliver To option.