If you are not allowed to access twitter at work or if your Boss still thinks after social networks sites decrease productivity, well then you can use – SpreadTweet which is a twitter client with an interface just like any Spread Application and comes in several flavors – OSX Office, Office 2003 and Office 2007. Spreadtweet is built on Adobe Air environment and is a small portable application. It has all features required. Download from http://www.elliottkember.com/spreadtweet.html
My suggestion, if your work place policies don’t let you use any, better don’t. If your looking for professional solutions, read my earlier post about the Best Twitter Client – TweekDeck and Twirl.