We did this in a yahoo group I'm in...
Here is what you need:
-Black permanent ink pad (Stazon, Memories, Ancient Page, Brilliance, SU Craft pads will work the basic black isn't really black enough)
-2-3 colors of reinkers
-Gold or any metallic reinker (if desired) or Pearl Ex powder!
-Clear glue (best to use a glue that is clear to begin with, crystal effects works well)
-Plain white tissue (gift wrap tissue)
-Acetate sheets (transparencies)
Instructions:
Stamp image on front of Acetate. Allow to dry. When completely dry, turn sheet over and place a nickle size amount of clear glue in center of image. Place 1-2 drops of each different colored reinkers on glue, add 1-2 drops of metallic, if desired. Start spreading glue and reinkers around the back of plastic until image is completely covered. Be careful and try not to mix the colors or they will get muddy looking. I try to keep the colors separate with just a little overlap. While still wet, take a piece of tissue paper a little larger than stamp image, crumple it and smooth back out. Place tissue over wet glue/reinker mixture and press until tissue is saturated. Allow to dry, cut out and mount to cardstock.
Here are some examples:
http://www.patstamps.com/TT_Acetate_Tissue.html
Hope that helps!!
Mary