Onnay Okheng

Add the official Google +1 button to your WordPress blog to let visitors recommend your pages right in Google search results without having to leave the page. Place anywhere on your template.
Google +1 is the first plugin to bring total Google +1 support to your WordPress site. It features template tag (both fully customizable on top or bottom of content) allowing you to place as many Google +1 buttons on your site as you want, where ever you want. It also comes with built in support for all 46 of Google locale / country API�s.
Here is the <a href="http://www.screenr.com/0HBs" rel="nofollow ugc">demo</a>.
Contact me for say hello <a href="http://onnayokheng.com" rel="nofollow ugc">Onnay Okheng</a> or buy me a cup of chocolate 🙂

Add Google PlusOne

It features template tag (both fully customizable on top or bottom of content) allowing you to place as many Google +1 buttons on your site as you wan …

athakur

This plugin adds Google Plus One Button to every post on your WordPress Site. 
This plugin is simple and uses in built function to display Google Plus 
One Button below every post. The size property of the plugin is set to “standard” 
and the annotation property is set to “inline”. Read about these properties here 
https://developers.google.com/+/plugins/+1button/

Add Google PlusOne vs WordPress Plus One Button