Edit: haha WildBlue beat me too it...
it seems daunting at times but its not to difficult just time consumeing.
i learned a lot from this tutorial.
http://www.youtube.com/watch?v=2mHTva5wepgthere is also this tutorial which is also great.
http://mlparena.com/index.php/topic,337747.0.htmli made my rehair tool from an exacto knife holder and sewing needles with the hole cut at a slant (they can break so you want a few) i also have a thicker needle to widen the holes before i poke the hair in. and i just use mod podge to glue the hair on the inside (get a whole bunch on a skinny cheap paintbrush and slosh it around inside till i think i got all the hair)
my method is:
rehair tool
wet hair (little easier and less mess)
~push bigger needle in hole to widen
~get a small section of hair about 15-20 strands
~fold in half over fingure tip (around the side of your fingure)
~Scoop up hair with long side of cut needle and hold hair semi tight to keep it from falling out.
~gently push hair and needle into hole should go in about 1/2-1 inch
gently poll out needle
~repeat
~once all holes are filled put a bunch of glue inside to hold hair in and let dry.
i hope that provided some help, it pretty relaxing once you get it. just set yourself up infront of the Tv and go!