I’ve got an indispensible iPhone app for social networking users. Yahoo rolled out on Wednesday a new app for iPhone that will let users manage a long list of social networks within one interface.

This long list includes some of the most popular networks today like Facebook, Flickr, MySpace, Twitter, Bebo, Friendster, Flickr, Lastfm, and YouTube. Not only that, it also lets users manage their mobile messaging in this same app. This app was described by Yahoo as “essentially a socially connected address book”.

The app’s feature, Pulse, will let you see the status updates of all your friends from these networks all at once. Your friend with the most recent update will show up on the top of this list. So iPhone users will no longer have to go to ten different websites to keep track of your friends. You can click on Pulse in oneConnect and you can see all your online friends instantly. If you find this list becoming too long, a separate Favorites list will let you select only certain friends to show.

oneConnect’s other function, messaging, is also designed to aggregate your communication from different channels. The app integrates instant messaging, text messages (SMS), and emails with the same friend into one threaded conversation. You can start your conversation with your contact over IM, then continue with SMS if you like. It will all be shown as one conversation stream, keeping it nice and organized for iphone users. For now, the IM function will work with Yahoo’s IM only (of course), but the company does expect other IM to be supported in the coming months.

Best of all, oneConnect is free. So get it from the Apple app store now.