Casting is fairly simple. What Iv'e used is either FME+SCFH or just xsplit. I prefer xsplit since its easier so ill give the tutorial through that.
1) Download xsplit here
2) There will be some rectangular buttons at the bottom left corner, chose the first one, then add a camera or screen region.
3) Add your JTV account, by clicking file, then saying add account or something along that line.
4) At the top row there will be a drop down that says broadcast, click it, then select JTV.

And BAM your casting. Just remember if you have your stream up at the same time to mute it, otherwise there will be extreme echoing. Hope this helped.

Here is the way to cast with Fme+scfh (the old way, the same that tom does it)

1) Download FME here
2) Download SCFH here
3) Unzip SCFH into a folder and take the one out that had the city image, and open.
4) Now open FME and you will get a thing in scfh that says something to do with fme. Double click on it to open it, then in Fme you will see something in the visual device, make sure that it is scfh.
5) Get your code thing off of JTV here. Then click config file.
6) After you get the file, make sure you know where it is. Then go to fme, then click file, open, then find the file that you got from the config, open it. Then save.
7) Now mess with the setting to see what works the best for you and your computer to limit lag, and manage quilty.
Now at the bottom click start, it will automatically go to your JTV and start to cast.
9) With scfh you can have select the area where you want to cast, with select area or something like that.
10) You will eventually learn more and how it works better.

Once again your casting. I dont recommend this way, since it takes more computer space than xsplit. But if you want to be like Tom use this way.

Thats great but how do i cast with game audio and my mic at the same time?

The FME/SCFH way is, in my opinion, really easy to set up and understand. No matter which way you go, FME is going to eat at your CPU Usage, so if you don't have very much RAM, then I wouldn't suggest broadcasting until you have more. I run on 2x4GB sticks of RAM and it's tough on my computer, but it's manageable.

As for the steps, I would put this in before step 7: Visit www.speedtest.net in order to view your download and upload speeds. This will help to determine what settings you should have for FME.

A good tip to use is to make it so that your kb/s needed in FME is half of what your upload speed is.
Ex: My upload speed is around 0.84Mb/s so I should be using around 500kb/s or so. However, I push it by having 700kb/s.

You can mess with it as you see fit until you have a good setting for your computer.

As for getting your game audio along with your mic through to FME, what I use is a program called VAC (Virtual Audio Cable). I had torrented it in order to not get the voice saying "Trial" every 3 seconds when I was using it.

I don't remember where I got the true version from, but if you look for it, I'm sure you can find it.

Even though you think that Fme is strait forward, you should try xsplit, it doesn't eat your ram, even though there aren't as many settings to fool around with , its basically fool proof. And I like it for if i play a game online my ping doesn't rocket up and i don't get kicked.

And i just wanted to post this, since i was 1 post away from thirty

Haha, you point dummy.

Anyway, the reason that a person would use FME is to get the good quality streaming. Without it, such as just using JTV and some other program, your cast will look crappy. Although I cannot vouch for Xsplit since I've only used FME in combination with VHScreenCap or SCFH.

FME I find less ram eating on my computer and xsplit was unreliable for me