hi, this script works very easy. first you have to know how actions works, so i recommend to read the tutorial, because my english is very limited.
create an action for each phoneme (control+k opens the action window), then, in frame one of each action, move your mouth points according to the phoneme, as if the actions would be switch layers. you can create the same name action in several layers which be inside the same parent layer (and obligatory the action must be created in the parent layer).
when you have this actions created, you can apply them in time. select your group or bone layer, go to the frame you want, select the action you want and push "insert reference".
you will see that your character will move.
an action can have points movement, layer color changes, bone movements, layer movements, etc.
as all the actions inside the bone layer has the same name, when you inset it in the parent, it will be inserted in all the child layers which have the action.
when you have all the phonemes created, and the lipsync generated in papagayo, you can use the script and insert them with the actions instead the switch (the layer must be selected).
it's very useful and generates a very different animation kind compared to switch, here is a simple example of actions:
http://tazatriste.cl/cosas_subidas/3/test%20mouth.anme
and here is a more complex characters which sing using this script:
http://tazatriste.cl/cosas_subidas/3/rinoceritis.anme
http://tazatriste.cl/cosas_subidas/3/jelp2.wav
right clic, save as both files.