Google has put up a sample webpage for webmasters where they can generate the HTML code for a Google Plus button and embed it on their websites and blogs. All you have to do is copy the URL of your Google Plus profile and enter it into the “Enter Profile URL” text field on that page:
Next, you can choose whether you want the button to link to your Google plus author page or content page. The size of Google profile or Google Plus button (whatever you call it) can also be chosen between small(16px), standard(32px), medium(44px) or Tall (64px). Once you have chosen all the parameters, the webpage will give you a sample HTML code which can be added to the design template of your website’s theme or as an HTML widget in WordPress, Blogger and other blogging platforms.
Here is the Google Plus button for my Google profile, hit me up on Google Plus if you want to connect with me:
Note that you can always download the Google Plus image, host it on your web server and generate the code using HTML editor programs like Microsoft Frontpage or Adobe Dreamweaver. But this one does a fairly nice job for anyone who has no idea on how to write <img> and <a href> HTML tags.