Nagmay

Based on twitpress by Tom Purnell. Adds the ability to choose which category will result in updates to your twitter account.
TwitCategory sends a tweet notifying your followers that a new post has been published on your blog. It is very customizable, allowing you to format the tweets using static text and several variables: title, post, permalink, guid and category name.
New versions also allow for URL shortening via tinyurl, isgd and bitly!
<h3>Upgrading</h3>
<ol>
<li>Click update from the WordPress plugin menu.</li>
</ol>
or
<ol>
<li>Click ‘Download’ on this page.</li>
<li>Deactivate the twitcategory plugin through the Plugins menu in WordPress Admin.</li>
<li>Upload twitcategory.php to your /wp-content/plugins directory, overwriting the previous version.</li>
<li>Fill in your twitter account information (be sure to re-enter your password), using the twitcategory configuration menu found in WordPress Admin.</li>
</ol>

TwitCategory

Based on twitpress by Tom Purnell. Adds the ability to choose which category will result in updates to your twitter account.

Konstantin Kovshenin

Twitter Embed requires no configuration, it works out of the box right after activation. Copy a link to a tweet on Twitter.com and paste it on a line by itself in your post or page editor. When viewing the post, you’ll see that the link has been replaced with the embedded tweet with options to reply, retweet, favorite and follow.
The plugin uses Twitter’s original widgets API, the shortcode and embed HTML are available too. Embed HTML is reversed to a Tweet shortcode when HTML is filtered (for authors or contributors). The tweets themselves are cached in post meta for better performance.

Twitter Embed

Easily embed tweets in your posts and pages by posting the tweet URL on a line by itself or by using a shortcode provided by the Twitter interface.

TwitCategory vs Twitter Embed