It's Easy For Your Formatter To Do This Social Media Linking For You...
If you wish, it is easy for your formatter to include links to your fan pages on Facebook, your twitter account or your blog. You should type a page with the needed information and links. Plan to put this information either on an “About the Author” page, or an Acknowledgments page, or even a Praise Page (relevant blurbs and reviews, placed in the front of the book so potential buyers can see good stuff about your book, upfront in the LITB, to help induce them to buy it.)
Please note that you should be careful about where you put what links. For example, don't put links to your book on Amazon for a book to be uploaded to Apple. Apple will reject it. Don't talk about your Apple book in an edition to be uploaded to Nook. Don’t put links to your books on Apple in your Amazon books.
How Do I Get People To My Books?
If you've done this before, you know what a pain it is to try to figure out what to do about the links. Do you keep an ePUB for each company? One for Smashwords, one for B&N, one for iBooks...you can see how this would make you pull your hair out. So, what's an author to do? A very good strategy is to make sure that you have a great landing page on your own website. Make all the links in your books go to that page. On that blog page, or website page, you can put links to all your books on all the retailers. This is the simplest way to do it. Also, if something changes, this way, you do not need to reissue the eBook (and pay to have it re-made!). You can make the changes on your blog page only. This saves you money and time.
And Don't Forget...
The Amazon Author Central pages! Far too many authors just blow off the Author Central pages, thinking "I don't want to just talk about ME!! That's boring!" And you're right, if that's all you did, it would be. But you can do all sorts of really cool stuff with Author Central; you can pipe your blog posts in there using an RSS Feed (trust me, it's not hard). You can put up videos. You can post announcements, and even have discussions on your own forum. Don't miss those opportunities!