How to upload Video on Twitter using Twitvid in iPhone application through programming?
I don't have code that I can give you, and I don't know of a library that does all that easily, but I'd suggest you to look over the TwitVid documentation: http://twitvid.pbworks.com/w/page/22556295/FrontPage
To accomplish doing the required OAuth requests, I suggest you use the ASIFormDataRequest class: http://allseeing-i.com/ASIHTTPRequest/