Twitter is one of the fastest growing social networking sites around and with all those new users have come new ways to use Twitter, in the form of customized applications that do everything from search for jobs to finding people with like interests.

For your convenience, here are my top 7 Twitter apps to maximize the usefulness of the micro-blogging site.

1. TweetDeck
TweetDeck allows you to create multiple columns with groups. For example, all your marketing contacts can appear in one column while another would show personal contacts or perhaps others interested in travel or another common hobby.

2. TwitterBar
This is a Firefox add on that lets you tweet right in your browser by adding a special toolbar. It is particularly handy for tweeting specific webpages that you want to share with friends.

3. Twhirl
For those who aren`t following huge numbers and just want a simple pop up application, twirl is perfect. It minimizes to your status bar and updates appear in brief pop ups and has all the basics for tweeting, retweeting and sending direct messages.

4. TwitterFeed
Named as one of the most useful Twitter applications by Darren Rowse, aka ProBlogger, this handy app lets you post links from your blog. To avoid the typical automated look, you can customize the message on your tweets.

5. Socialoomph
This tool lets you set up scheduled tweets, something that is particularly useful if you`ll be on the road or live in another time zone from the majority of your audience. If you schedule blog posts to go live at a specific time, you can now schedule a tweet about it, as well.

6. Twello
Lauded as the Yellow Pages of Twitter, this site lets you find people on Twitter in specific professions or areas of interests. If you`re interested in advertising and marketing, for example, Twellow will give you a useful list of people to follow.

7. TwitScoop
Looking for what`s hot on Twitter? TwitScoop lets you see at a glance what people are tweeting about. You can see all the most popular keywords in a tag cloud. This application is actually integrated right into TweetDeck, for added usability.

What are your favorite Twitter applications? With the hundreds now in existence, I`m sure there are some I haven`t used that could be very useful.