This tutorial is for Mac users looking to stream gameplay (with picture in picture) to Twitch.tv from your Mac. Program links can be found below! Feel free to ask me any questions you have! You already need to have a capture card and a Twitch account for this.
CamTwist – http://camtwist.en.softonic.com/mac
Adobe Flash Media Live Encoder & Profile – http://www.twitch.tv/broadcast
Soundflower – http://cycling74.com/soundflower-landing-page/
LineIn – http://www.macupdate.com/app/mac/11333/linein
There a multiple ways to do this… These are just the programs that have worked for me! All opinions expressed are my own and feel free to ask me for help! Please note that this process is very CPU intensive and that your machine can handle this. I also highly suggest using a second computer, tablet, etc to open your twitch chat to cut down on the processes open on your computer.