If you have time to work with raw textures in a generic mapping tool, take a look at Genetica, there is a free download "viewer" application, and it has some pretty ice and snow presets: http://www.spiralgraphics.biz/packs/snow_ice/index.htm
The licensing of graphics rendered from the presets is free for personal use (see http://www.spiralgraphics.biz/packs/usage_rights.htm), and the viewer can be downloaded at http://www.spiralgraphics.biz/viewer/index.htm