Looking for a tile slideshow transition effet
Here is something similar, http://www.mihaipanait.com/portfolio-items/hexagon-transitions/

I know Noise Industries used to have that effects with squares and I am sure you could make the squares into hexagon shapes if you wanted...but their website seems to be down at the minute

Also check out videohive.com they have some pretty cheap templates for transitions etc and you may be able to find something that you can tweak to make work