WP Social Toolbar plugin by daddydesign will display your latest tweet, list your social networking profiles, and allow users to “Like” your page on Facebook or tweet about it on Twitter!
This plugin is also heavily changeable. You can specify colors and fonts, and rearrange your list of social network icons to your desire. Display it on the whole site or just the home page or just the blog or even just an indivdual page.
Plugin homepage (which uses plugin): http://www.daddydesign.com/wordpress/social-toolbar-wordpress-plugin/