fiskeben

Adds a link to each post that points the user to Twitter.com. Before the redirect, the URL for the actual post is sent to Tinyurl.com and the tinyurl-ified URL is used as an argument to Twitter.com thus putting it in the status field when the page loads.

FishyTweet

Adds a "Tweet this" link to posts, shortens URLs with tr.im or TinyURL and sends the user to Twitter.com.

Sand Fox

Juick Crossposter automatically posts title and link of your new posts to the Juick.com microblogging service.
<a href="https://wordpress.org/extend/plugins/xmpp-enabled/" rel="ugc">XMPP Enabled</a> plugin is required

FishyTweet vs Juick Crossposter