New addition to blog: Tweetie 2.0 has been released ($2.99 in the apps store). It’s better than other. You’ve got to check this one out!
There are plenty of iPhone apps for twitter use from which to choose. At this time the continuing leader (and still champion?) is Tweetie. However more tech savvy users may want to take a test drive of TweetDeck.
Both offer a lot of flexibility in connecting your phone, with twitter, with the rest of your favorite social media sites. TweetDeck is probably a bit more powerful, but Tweetie is much more user-friendly in a head to head battle.
Mashable has a good, competitive review of the two in a head to head test that is definitely worth a look.
For iPhone and other mobiles, you can take a look at Logpost, which claims compatibility with most major platforms.
Business users of Twitter may have multiple Twitter accounts. If this applied to your situation, you may want to consider LaTwit (you gotta love that name) which will support multiple accounts.
If your major activity is tweeting interesting posts that you stumble across to all of your followers, Twitterlink may be your cup of tea.
Everyone uses Twitter differently. Consequently, there is probably not a single app that is right for everyone, but there are certainly plenty of choices.
Tip* to deliver updated content daily on twitter, you can utilize a news aggregator or RSS feed, you can also post at planned times during the day. The max. tweets that you should post per day must be between 2 and 4. more than 5 tweets is overkill.