How to achieve this effect?

I was curious as to know how to achieve the effect on the photo below:
http://gallery.ipodlounge.com/ipod/albums/userpics/2in1.jpg

The description of the picture says that two cameras were used but no photoshopping was done. Still not sure how he did it... Is there any way to do this with just one camera? Thanks guys!

You have to set the exposure lenght to a few seconds. When you take the picture, activate your flash once and then another time right after. You should come up with a similar effect.

hmm, dunno if you understand, but if you don't just ask.

I don't quite know how to "activate" my flash twice... I have a Canon Powershot s400 by the way. Thanks again!

I don't know if you can do it with your camera. I guess you gotta read your manual to see if it's possible.

Set the camera to Shutter Priority if you have it, and set the shutter length to 2 or 4 seconds. Play around with it to find a good length.

If you can control the ISO settings of your camera, set it to a higher ISO setting so it's more sensitive and will take in more light. This could also make the picture grainy. If it does, use a lower ISO setting and a longer shutter exposure.

Deker has it there lol.

The photographer used the second flash from another camera.

you can montage it. taking 2 long exposures and adjusting the opacity in PS. Or you can set your powershot up with the flash with a long exposure, then use another flash, and pop it with the recycle button on it. It may help to have a friend to help you out