Okay, I know some DJ's new and old have a lot of trouble with this, and I've found a few ways to do it myself so I thought I should make a tutorial so everyone can do it too~
Also this isn't a broadcasting tutorial, I don't want to reveal any secret DJ infos, haha.
Sound Blaster Audigy Soundcard(Credit goes to Odango for teaching me this one)
Okay, so the easiest way to do this, is with a SBA soundcard, and a regular wired mic.
Although in saying that, other kinds of soundcard might have something similar to the 'what U hear' mixer channel that the SBA card has, so your card could work too.
Go to the volume controls, and set your settings like this.
Notice that the microphone option is unmuted, this is on purpose as what you are hearing (or 'what U hear') is what is going to be broadcasted via Oddcast, you
will hear yourself speaking, but with this option it's in real time with no lag, so you get used to it, plus headphones are good to prevent any feedback problems from this.
Set your Skype settings like this.
As you have set recording to come from 'What U Hear' this will be your audio input to Skype, so the other person(s) will hear both you and your music, if it is playing.
While broadcasting, keep the volume controls open. This is because Skype likes to mute the microphone through 'What U Hear' as soon as you connect a call with someone, so simply unmute the microphone via the volume controls. Another potential problem is if Skype sometimes decides to change 'What U Hear' to 'Microphone' again, with the volume controls open, you can override this and change it back.
(One problem with other sound cards is that, you
can't override what Skype does, however with an SBA, you can, which is why it's useful to have one)
The last thing you should do is set oddcast like this: (yes my windows theme is purple)
The mic is uncrossed just to show you the settings btw, just use that box as normal when you want to play songs.
So, all you need to do now is call someone or have them call you (making sure to keep an eye on the volume controls while you connect to them) and you can have as many guests as you like!
The only drawback with this method is your own mic volume can end up being a bit low even with mic boost on since it's going through the mixer, but that might just depend on your own set up.
I'll update this topic with more ways to do it as soon as I do the tutorials for them lol.