I've seen this pop up more and more ever since the TMD online open kicked off. I decided to gather some of the resources I use to help others get to streaming as well.
Look at this cute PDFAll credits for this awesome tutorial should go to this guyI just created the PDF.
Also, keep in mind that the latest iMac's don't have a line in but only a line out, to get an actuall Mic to connect (don't use the inbuild one as there's going to be a lot of noise, get a decent headset or Mic setup) you need the following little USB device.
iMicJust about every Apple store will have this and it's going to be the best 40 bucks spent when you're looking to get into doing something regarding audio.