TweetGlide

TweetGlide is yet another client for Twitter, based on Adobe Air, that allows you to manage multiple accounts.

It has the plus of being a marketing tool as well, so website owners and people involved in online marketing will find it useful. Its interface looks very similar to TweetDeck --the most popular Twitter client. The main window is divided into columns, called Glides, showing your timeline, direct messages, mentions, favs, and sponsored tweets. You can arrange them the way you find most convenient, moving or hiding glides at will. With the buttons below each glide you can manage your messages: Clicking on "show what's popular" will activate a small area showing the popular hashtags and users. And the "filter this column" button lets you search for tweets filtering the results by username or keyword.
To compose your message, TwitterGlide offers some cool options as well. To start with, it integrates a list with a number of URL Shortener services, so whenever you want to share a link with your followers you paste it on the 'tweet' area and it gets automatically shortened, just like in TweetDeck. A similar feature is available for sharing pictures: simply by dragging and dropping an image into the 'tweet' area, the program will upload it, providing a short link to it. In addition to this, TweetGlide allows you to tweet messages longer than 140 chars. It does so by posting a part of your message with a link to a website where the complete message can be read.
From the settings panel, you can select the Pic services and URL shorteners that you want to use, determine the time interval to update your messages, manage other Twitter and Facebook accounts, users, etc.
The only drawback I found was that, in difference with TweetDeck, TweetGlide does not display alerts notifying you about new twits. Even so TwitterGlide proved quite stable and reliable for an application in Beta stage.