OK... nice compliment (thanks!) and a capitalized "PLEASE"... guess I'll have to spill the beans...
The first picture below is pretty much it. I made a hemispheric dome (from 1/2 a small plastic Christmas ornament) and spray painted the inside lightly with a matte white paint. Then I cut a hole in the top so that it would be a "press" fit over the front of the objective I like to use -- a Nikon 3X. (The dome is mounted a little "skewed" in this snapshot). The objective is an odd, older one, with an exceptional working distance. When a slide is in place and focused, the lower edge of the dome sits about 3 or 4mm above the stage. On either side I have a fiber optic light guide directed onto the surface of this mini "diffusion dome". I now use focusing lenses on the light guides. They are not really necessary, (I've done many shots without them) but they do allow keeping the guides "backed off" and out of the way, and provide a nice amount of adjustment by sliding the guide in and out of the lens. By moving the guides in the lenses, and moving them up/down, in/out, back and forth, you can really vary the lighting effect much more than might be expected. Broadly illuminating the dome gives a more diffuse light. Moving a guide in tight so that it only illuminates a small spot on the dome gives much more direction and "dimensionality" to the light.
For some subjects this technique may be too "soft", but it does wonders for faceted eyes, shiny beetles, and iridescent wing scales.
Underneath the stage you can see that the condenser has been removed. A piece of green semi-transparent paper has been placed on the condenser carrier, and this is then illuminated by the microscope light. This provides the background color.
This second snapshot shows how the subject is held under the microscope. (In this shot the slide is resting on a piece of black foam, it is not on the microscope stage). I take an old slide and attach a thin strip of brass with a gob (I think that's the appropriate technical term!) of epoxy glue. Then I examine the specimen under a low power stereo-scope and determine the angle I want to photograph. The subject is then fastened (usually with cyano-acrylic adhesive or epoxy... Elmers if I want to be able to remove the adhesive with water) to the brass strip as close as posible to the orientation I want. Then, under the stereo-scope, I can bend the brass strip any which way with tweezers to get the orientation "perfect". Notice that the subject is held out in the "air", not over the glass of the slide. It will extend out over the opening in the microscope stage. If you mount the subject over the glass slide, unwanted reflections from the broad "dome" light source will drive you crazy. (As can reflections from the condenser glass if it is left in it's normal position). Preparing and adjusting these specimens for photography became so much easier once I started using these brass strips as shown here. They are stiff enough to hold the subject rigidly, but can be easily bent into just about any orientation desired.
So there you have it! The Nikon Small World fly picture was done exactly this way, but I used a Zeiss Plan 2.5X, with a "dome" made from 1/2 of a ping-pong ball.
