1. Set up a Far Side RSS feed as described in my blog post, or find somebody else who already has and get in touch to ask them if they’ll share the URL.
2. Use a free service like Blogtrottr, Zapier, IFTTT, FeedRabbit, or even MailChimp to monitor the RSS feed and email you any new entries to appear in it.

Note that the technique I describe above might not result in the image of the comic being included in the email: just a link to each individual comic on the site as it’s published. You’d have to try it to find out, though. If you have to do a little extra work to get the images, it’s certainly very achievable: but that’s an exercise left to the reader. Doing so may violate the terms of use of the Far Side website, so read those carefully first too.

Alternatively, or in the meantime, you could suggest it as a feature on the Far Side website.