HootSuite has been one of the most popular Twitter clients around. People specifically like it for its unique features like multiple Twitter accounts support and tracking your shortened URLs.
Well, HootSuite is just getting better each day. They just added support for Facebook and LinkedIn as well. So now you can manage three of the most popular social networks from a single application. To add your Facebook and LinkedIn accounts, simply click on settings and follow the instructions. If you need help doing that, here are some detailed instructions.
Not to forget that HootSuite lets you schedule Twitter messages for future, and now you can do the same with Facebook and LinkedIn. Moreover, their iPhone app is supposed to be in the works too. With these many features, HootSuite is bound to give a tough competition to huge clients like TweetDeck and Seesmic.