I just made a couple of textures:

http://ia300106.us.archive.org/1/items/Snow_4/snow.jpg

http://ia300142.us.archive.org/2/items/Globby_snow/snowblur.jpg

One is globbier-looking than the other.

Use the high-res square (Poser 6 primitives). Turn it 90 degrees, so it faces the camera. Then attach one of the textures to both the diffuse node and the transparency node.

Image is how it should be hooked up in the material room.