Seesmic

Seesmic for iPhone lets you update and view multiple social networks in an efficient and powerful application. Manage multiple Twitter accounts, your Facebook account, your Chatter accounts, a Ping.fm account and organize all your accounts, searches, trending topics and lists in your customizable dashboard.

Features include:
✔ 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 with ability to see your newsfeed, your inbox as well as your list of Friends and Pages
✔ 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!)
✔ Post to multiple accounts at the same time
✔ Store updates into Evernote
✔ Save links to Instapaper and Read It Later
✔ Share photos to the photo sharing service of your choice
✔ Tons of other great features!