Google Plus One is a new way of indicating that you like an article, similar to the thumbs up or "like" on Facebook. It connects to the new Google Public Profile interface. At this point, you need to be invited to join this, but you can consider yourself invited, by clicking http://gplus.to/sharkbytes.
Then, in the post where you would like to have the button show, add this <g:plusone></g:plusone>
You can see that I successfully added it to this post. If you want it to appear in every post, make it easy on yourself and put the <g:plusone></g:plusone> code in your post template- that template of items that you want to show in every post.
You can also add the Google+1 icon to regular web sites, using the same method.
If you found this helpful, maybe you would click the +1 button below for me!
Google +1 FAQs