PicPing is an iPhone app we just released as part of the Globe MobApp Hunt. It allows you to connect your Facebook, Twitter, Flickr, and Tumblr accounts. You can then take photos and upload it to all your accounts in one go. It is now available for download on the App Store.
I made this using Cocoa Touch / Objective-C. Of all the available social networks, the easiest to integrate was Facebook because of their iOS SDK. The examples were really easy to follow. Tumblr comes next because of their very simple API. I used ASIHTTPRequest for communicating with it. Flickr integration was also a little easier because of ObjectiveFlickr.
Unexpectedly, I spent the longest time with Twitter. There were so many available iOS libraries for Twitter that I couldn’t figure out what to use. And I found most of them to be really hard to understand and start working with. I ended up with this library by Ben Gottlieb for authentication and Twitter posting. I used PlainOAuth and ASIHTTPRequest for communicating with TwitPic. It was a mess but I didn’t have enough time to clean them all up.
To summarize, I wouldn’t have finished all these integrations if it wasn’t for all the awesome open-source libraries. Thanks to all the authors!