It is not a particular software. The changes come from added effects called "Plug-ins" I researched this for about 2 weeks and read up on forums and tried to gather as much knowledge about them as I could. I was exactly where you were about 6 months ago.
I like sound forge much better than acid for voice overs... Good equipment and good vocal control make all the difference in the world! If you don't like the way it sounds before before adding any effects you won't like it after the effects either... Try adding some distortion to really make the voice POP over the music