For making voice line replacements, all you really need is the voice clips of your choosing and knowing where the taunts folder for your character is.
For editing the clips, you'll have to look up the source, put it in a audio editing program (Audacity) and remove everything but the quote (for this example I'll use the 'Let it die' scene)
Some clips might already be cut and posted on YouTube because of how ironic they are - I am your father and what not - so you might be able to find them that way as well, but your guaranteed to get a higher quality sound by editing it by hand.
Once you actually find the source and put it in Audacity, you'll want to edit it by finding what your looking for, select it, playing it to see if it sounds alright (making adjustments if necessary) then clicking File in the top left hand corner and Export Selected Audio. Name it, place it somewhere easily accessible or where you can also remember it.
Next open the characters taunt folder in "zz_MBModels2.pk3\sound\chars\\misc " in WinRar. Put your clip in there, name it taunt# whatevers next and that should be it. Tell me if I forgot something
