ruudkok

With this plugin you can add the new Tweet button from Twitter to every post, and every page. The plugin is fully customizable:
<ul>
<li>Choose where to display the button (top,bottom,left,right), up to 2 times each post/page</li>
<li>Choose when to display the button (posts, pages, both or everywhere)</li>
<li>Select the type of button you like (horizontal count, vertical count, or no count)</li>
<li>Set the margins between the Twitter Button and surrounding content</li>
<li>Select a twitter account (if any) which you want to be mentioned in each tweet (e.g. via @ruudkok)</li>
</ul>

WP Twitter Button

This plugin allows you to add the new Twitter button(s) to your blog. You can choose the type of button and set where to display the buttons.

LaClave

The MasDetalles share plugin to help people share, bookmark, and email your posts and pages using Masdetalles share. New: MasDetalles share.
MasDetalles Share le permite compartir sus enlaces en el marcador social Masdetalles.do desde su blog, email, tienda virtual, y cualquier pagina web.

Masdetalles Share

Help people share, bookmark, and email your posts, pages, your favorite links through MasDetalles.do

WP Twitter Button vs Masdetalles Share