With its main competitor, Seesmic Desktop, just upgraded to a new version, TweetDeck has also received an upgrade of its popular Twitter desktop client, keeping the competition alive. TweetDeck was just released as an iPhone app and, to coincide with the launch, a new version of its desktop client has also been made available. The main piece of news is the iPhone synchronization but the latest version also comes with a full set of new or improved features.

“Today, we’re taking a step closer to that goal. From our humble beginnings just one year ago, we’ve had such an overwhelming response from you, our users. Your support and ideas have helped get TweetDeck to where we are today – building a team in London, constantly improving the product, and trying to change the way people view streamed, real time data from the Web,” wrote the creator of the software on the TweetDeck blog.

With the launch of the new iPhone app the team behind TweetDeck is also introducing synchronization between the two pieces of software, meaning that a change made on the desktop, like groups or columns, will also be made in the iPhone app and the other way around. But the desktop client also brings some new features to keep it competitive and among the biggest are multiple accounts and unlimited columns, up from the previous limit of 10.

The multiple-account feature was requested by some Twitter power users who manage multiple Internet personas. The feature is implemented in a very straightforward way and it's easy to tweet to one or more accounts using the input box. Some other small features include a “Block and Report Spam” button, which does what the name says and blocks the specific user but also reports him to Twitter, as well as “Reply All,” so you can automatically reply to all Twitter users mentioned in a tweet.