Maybe it was something like this.... http://www.vat19.com/dvds/instasnow.cfm
or here are a few DIY ideas but the link I listed for you looks like better stuff.
The following materials used to make artificial snow are not guaranteed not
to damage some surfaces. Cover surfaces you're unsure of with clear plastic. Use common sense, and always supervise children
when making and using artificial snow.
Salt and Powder Mixture
Many people who want artificial snow recommend mixing sugar and talcum powder, but sugar attracts ants and if it becomes wet it creates a sticky mess. Instead of using the typical sugar and talcum powder mixture, try table salt and powder. Table salt provides the same crystal-like appearance, and it works just as well as sugar. Mix together equal parts of ordinary talcum powder and salt, and let it snow!
Pure white soap flakes also make great artificial snow. Visit the laundry aisle of your local discount store and you'll find boxes of soap such as Ivory Snow. Although powdered soap isn't your cheapest option, depending on where it's placed, it can be scooped up and reused.
Dehydrated potato flakes aren't usually pure white in color, but from a distance it looks real and makes fantastic fake snowflakes. Potato flakes are lighter in weight
that soap flakes, and they're large enough to look like the real thing. When tossed they cascade gently to the ground like real flakes of snow. This is one of the best products
you can use for a display that requires falling snow, and it's relatively inexpensive
compared to other options.