Extremely Important For Current Movie!!!! Please R, Need to know how to manipulate voices Options

[flamingoblood2]

I am working on a movie and i need to make a regular voice minipulated in such a way so it sounds extremly strange and quite frightening. Such as mothman, if any of you have seen the mothman prophecies. I am looking for a software, not a hardware solution. Looking for fairly simple interface. I'm not excatly an audio genious! Please im a big newB and need some help.