This page has links to Nikon SB-R200 reviews and user opinions, sample photos and references.
The SB-R200 wireless remote speedlight flash was announced on November 1st, 2005.
8 SB-R200 speedlights to form a powerful ring flash
V_Kids has posted some very interesting photos and portraits showing how eight SB-R200 flash units can be mounted on a Carl Zeiss 85mm f/1.4 lens to form a ring flash powerful enough to shoot in broad daylight. Camera used was the Nikon D3. Here is a link to the forum discussion where larger photos can be viewed.
10-Oct-2008 update: I met Rener Tan of ConceptShots.com today at the Sony A900 launch at the Le Meridien Hotel in Kuala Lumpur, and he told me of a more compact approach for turning your Nikon speedlight flash into a ring light, which is to use the Ray Flash Ring Flash Adapter. Here are some related links:
Resources
Official web page for the SB-R200
Nikon USA has details on the key features and specifications.