Twitter with an exponential growth has left no choice for businesses but to join. And not just join, have their each department join with a separate account. Which becomes crazy when few people are tweeting for all accounts at the same time. Specially when talking about small businesses and specially website owners. Twitter is not only good for popularity with word of mouth advertising, but it also helps with SEO because it tends to rank high with status updates and the profile page keywords. Which is why I am seeing a trend where webmasters are making separate twitter accounts for each of their websites. Also some people don’t want to relate their personal life with business which is why they make separate twitter accounts. Well if you are one of them and are looking for a feasible solution to manage multiple twitter accounts this article is for you.
The method of logging out each account and logging back in is very inconvenient. Well since I have multiple twitter accounts myself, I have tried out multiple services before I picked the ones that I use. This list has a lot of options, although I will highlight which ones I use.

It has no limitations on how many accounts you can use. Each account will be on a separate column makes it very easy to manage. It is a strong desktop client which is very efficient in running. It can also be integrated with Facebook. I tried this one, but I did not like the look of it, but it has gotten a lot of positive reviews on other websites.
HootSuite is a very powerful web based script which allows you to have as many accounts as you like. The best part is, that you can have multiple administrators as well. It works out well if more then one person in the company is working on the twitter accounts. HootSuite also lets you schedule tweets ahead of time which is very convenient because there are sometimes in the day when more people on twitter are active. HootSuite lets you post to ping.fm as well. If you use their url shortener, ow.ly, it also shows you the link stats. I am currently using HootSuite to manage my twitter accounts because it is remote as it is a web based script. It is completely free of charge.
Cotweet is a very powerful software which is still in Private Beta. I unfortunately have not tried it, but I saw a lot of good reviews on the web. This is a software that many major companies are using such as Pepsi, Starbucks, Ford, Microsoft, Sprint and others. It adds a strong business layer which means multiple users can use the same account. It prevents duplicate tweets, allows scheduling, allows assigning of tweets to coworkers and users can leave note for each other. Since it is in Private Beta you must apply and hope you get accepted.
Twhirl is one of the most famous powerful desktop client that gives Tweetdeck alot of competition. Twhirl stands at #6 in Twitter Client Stats. It allows multiple accounts and cross posting to ping.fm
Twibble allows users to manage multiple twitter accounts. It also includes viewing options, location awareness, and keyboard shortcuts.

Tweetie for Mac is a very cool software for Mac OS. It also has a version for iphone. Tweetie for Mac does an excellent job managing multiple accounts and keeping the screen less cluttered. The powerful keyboard shortcuts are just what power users love.
Nambu is great for managing multiple accounts at Twitter, Identi.ca, and Laconi.ca. Nambu account holders get to use tr.im to shorten their urls and pic.im for better quality photos then twitpic. It also includes Twitter trends, saved searches, filters, link aggregation, and groups. Nambu all to all is a great software. It is also free for iPhone.
Tweet Later lets you manage multiple accounts, and have bulk scheduling options. It can also let you set up an automated DM for your new follwers. Remove people who are not following you. And it has more options for professional accounts which is paid.
Twittbot allows you to update multiple accounts at the same time. It also allows multiple accounts to update one account. It sets up bots that looks for @replies to be reposted to an account specified. The security levels of these bots can be adjusted. This is perfect for twitter accounts that aggregate stories from multiple places.
This is originally designed for businesses that want to manage multiple accounts. It allows tracking of brand mentions, but this software is not as good as HootSuite or as CoTweet defines themselves. I suggest you try HootSuite instead.

Digsby is a one in all solution for all your needs. As Digsby combines IM, Email and Social Networking at one place. It allows you to manage multiple twitter accounts, and it can handle your other social profiles as well. It has features that lets you manage your IMs from all different messengers. You can also manage your emails from different service providers as well.
Matt is a fully carsonified version of updating multiple twitter accounts. It is a simple web app that lets you update multiple twitter accounts.
An advanced, Web-based Twitter client that supports grouping, Facebook, stats, multiple accounts,
pretty pictures, trending topics, and all sorts of other cool, awesome, and fantastic stuff
Thats what I got from their website. Never used this site before, but I heard integrating with Facebook is one of their strong points.
Twitterfox is a firefox extension that lets you add multiple twitter accounts in the bottom right hand corner of your browser. You can browse through them in a single column view as you choose. I have this installed in my firefox. I had it activated, but then I unactivated it because I am a true HootSuite user for the most part, or WEB Directly.

Famous for its superb quality iphone app, they also provide a desktop client for Mac. It is a free app for iphone that lets you manage multiple accounts in a very organized way. It also has advanced search features. Same features are in the Desktop Client for Mac.
If I have missed any software or application here, feel free to let me know in the comment box. Also if you have used any of these, and you have a preference, please share it with others, so they can learn from your experiences.