Camera(s) connected to your capture device or directly to your computer used to push the video to your computer.
A computer that can handle live streaming; one with sufficient hardware and a good connection to your local Internet via a cable instead of a wireless connection. A wireless connection can work under the proper circumstances, but a hard line connection is preferred. Also, see this post regarding connecting over long distances from computer to modem.
Optional; an application that manages the programming that you are sending downline to the stream. Example, a switcher that can choose between cameras and desktop so you can stream more than just a camera input. Example apps would be ManyCam or Open Broadcaster Software.
Below is an example live streaming setup. This sample user has 2 applications running at one time during their live stream. ManyCam is used to capture 2 sample cameras video input (Blue and Red). Then Adobe's FMLE application captures what every ManyCam is passing to it and is pushing the video feed up to their EZWebPlayer Player that is hosted on their web site.
Using an application like ManyCam you can have multiple cameras going at one time and you can transition from 1 video feed to another. You can use transitions, text overlays, use playlists, images, music and so on. Adobe's FMLE will live stream what ever you do on ManyCam. It is kind of like a sound board but for video.
There are web media hosts that act as both the packaging app AND the streaming agent. EZWebPlayer is not one of those. EZWebPlayer is your web agent that packages the programming stream with professional and very useful tools for broadcasting your stream in multiple locations simultaneously such as 1) to the Internet at large, 2) on your web site in a special stand alone player page, or embedded on your web site, 3) Social media, like Facebook. But, you will still have to have a streaming agent like Adobe FMLE or Open Broadcaster.