Twittelator Pro is one of best twitter apps for iPhone and iTouch. It has many features like grouping, multiple twitter accounts, advance search, and even recording videos and sharing them on twitter! Check all features here.
Twittelator is not a free app. You can buy from the app store here for $4.99
Pros & Cons
|Simple cool interface||Not a free app!|
|Huge number of cool features! Check all features here|
|Integrated with many other twitter apps|