SAMBroadcaster is a fairly sophisticated piece of streaming software designed for online DJ's. In our experience, it has proven to be the most reliable way for Windows based webcasters to succeed.
This software has a lot of different options that may be too complicated for the beginners. Secondly, the main idea behind SAMBroadcaster is to not only stream voice but also to play music. So if you don't plan to play music during your show, I believe that using other software (like Oddcast or Simplecast) should be enough. However, there are many exceptions in the field of live webcasting and this is one of them. You should try streaming with few programs and see which one is the best for you and which one gives you the best voice quality. Remember that hardware of you PC/laptop and peripherials can influence the live stream in many ways: starting with the voice quality and ending with keeping constant and good internet connection or stream. Thus, live webcasting is like an ongoing experiment; but it's fun!
Screencast Video#1
Screencast Video#2
Conrad's Screenshot Video of how to use Sam to webcast without Virtual Audio Cables