Additionally to the previously discussed masters (Dave Black, David Berman- also known as Sitbonzo and Dave Hill) I must mention a photographer working in New Zealand. I found him through an article on Strobist – the blog that is about teaching the digital photography community how to use flashlights off the camera. The article is about Brent Williamson who is using one remotely controlled flash and the Sun as light sources and makes amazing portraits with this technique.
His blog is the Stateofthenation and this is his Flickr photo stream.

All these guys inspired me to take the photos below. Bear with me, these are my first shots of this kind.

My best and most patient models: my family.

I used my Nikon D80 and a still borrowed Nikon SB-800 speedlight. My wife was standing with her back to the Sun and I placed the flash on a tripod opposite to the Sun a bit above her head level. The D80 built-in flash was in commander mode where I disabled the built-in flash itself (it flashes though once for TTL, but not when taking the picture) and the SB-800 was in remote mode and manual. With this scenario I could adjust the output level of the remote flash from the camera. For this shot it was 1/2 or 1/4. I also used the diffuser dome from Nikon supplied with the SB-800 attached to the speedlight.

I did not have to use any transmitter-receiver devices other than the camera and the flash themselves.
I know that from artistic point of view the composition of these shots are far from perfect and the light could have been more ambient. The shadows are quite strong but I kind of like them this way. My purpose was to make eye-capturing portraits.

And a behind the scenes photo at the end with my lazy assistant