I have had Seesmic on my Google Phone for a while and I like it for what it does. (Seesmic was available on Android and BlackBerry for a while now). Looks like I will be able to use Seesmic on iPhone now.
Seesmic just announced the app for the iPhone and is in the App Store.
Features include:Looks like something I need!
✔ Seamlessly manage multiple Twitter accounts
✔ Explore and save Twitter Searches and Trending Topics
✔ Browse Twitter Lists, share your location by Geotagging your updates
✔ Facebook support
✔ Ping.fm support that lets you update dozens of social networks at the same time (including MySpace, Wordpress, Tumblr, LinkedIn, Flickr, Blogger, and many more!)
✔ Store updates into Evernote
✔ Post to multiple accounts at the same time
✔ Share photos to the photo sharing service of your choice
✔ Tons of other great features!