Eye Candy is available from Alien Skin Software (http://www.alienskin.com/eyecandy/). It's not a freebie although you can get a free trial version.
Truthfully, faux snow can be easily done without third party filters by using the noise filter and some creative scaling and blurring. There are plenty of tutorials out there; here are two from the same site: http://www.photoshopessentials.com/photo-effects/photoshop-snow/ and http://www.photoshopessentials.com/photo-effects/photoshop-weather-effects-snow/