WizyLike Like/Unlike by CodeCanyon
WizyLike is a WordPress plugin that allows registered users or visitors to like or unlike your blog posts. It allows the user/visitor to like your post one time only and unlike it if desired. WizyLike has 3 style options and 12 colour options for maximum customisation. The mark-up is dead easy to style so if ready made styles doesn’t suit you, go ahead and make your tailored style.
WizyLike Like/Unlike demo: http://codecanyon.net/item/wizylike-likeunlike-wordpress-plugin-for-posts/141290