I have been doing some experimentation with different lighting techniques since getting my Flash Waves radio triggers. Here are a few macro samples of flora from around my yard.
Getting the flash (or flashes) off the camera certainly lets you control your lighting much better.
Dual FL-36 flashes. Shoot through umbrella to the right about 4 feet from the subject, with flash on full power.
Another FL-36 strobe with home made snoot and grid in close slightly to the left set to 1/32 power to make the purple leaf stand out from the background. Without this it was rather dull.
Backlighting is a technique whereby you light the subject from behind. That is, the light source (or sources) is in front of the camera but behind the subject. If the subject is opaque in nature such as the kiwifruit example you get a nice glowing effect.
You can take a couple of different approaches with this type of photography. Use available light, off camera lighting or a combination of both.
With my example here I needed a controlled environment so went with a single off camera flash triggered by a Flash Wave radio trigger. I also wanted a Hi-Key image which emphasized the dark areas of the kiwifruit slice (something a little different to the thousands of other kiwifruit images I have seen on the Internet).
Updated 3rd August 2008
I am currently researching Radio Triggers to remotely trigger off camera strobes (flashes). This will allow me more precisely control my lighting and help me to develop my creative side.
What I am looking for initially is a setup with 1 transmitter and 2-3 receivers which will allow me to have a flexible setup for different circumstances.
On a side note, I will be using Olympus flashes FL36/FL50. While I know that the new FL36R/FL50R flashes have a good remote capabilities - via the inbuilt flash (with supported bodies E-3 E-420 and E-520). But, I currently shoot with an E-510 and non R flash.