The "Caustics Generator" is available in both freeware and commercial versions at http://www.dualheights.se/caustics/ 
You can make very good caustics animations with the freeware version. I haven't tried the commercial version yet. I've also used Caustics generator to make greyscale animated displacement maps for pretty credible waves in Carrara. To do this just add a lot of blur so the waves are not so sharply defined.