Ok, this is very cool takes a while, but once you get it, it's easy.
Check out this step by step guide - http://neil.creek.name/blog/2008/02/28/how-to-see-3d-photos/
Don't do it for to long or you may get a headache etc.
I would love to see some corals or full tank shots with this 3D effect.
Get shooting boys.