Those who use Tweet Deck may have noticed that deck.ly which facilitated tweets of longer than 140 characters has been withdrawn from the app. Thanks to @bw58 for pointing this out.
Here are a couple of tips that remove the issue. If you RT from Tweet Deck or other apps you might struggle for space. The solution is to RT from twitter.com using the link that appears underneath a tweet when you select it. If you retweet using this method there is no character limit.
If you need lots of space then linking to a post on Google+ could be a good workaround. Just select the time of your post to obtain the permalink (another tip). With formatting, photos and video you can even blog on there (there’s another tip). The advantage of using Google+ is that you’ll attract visitors to content they won’t find on Twitter. There’s no problem if readers of your tweet aren’t on Google+ as your link will work for them and they’ll be able to read your post.