Interactive Desktop Snowfall is the further development of my Desktop Snowfall. Here snowflakes fall down and settle on windows and the taskbar. But the main feature, which differs Interactive Desktop Snowfall from other desktop snow software is that by moving you mouse you can create air currents, which will take snowflakes in certain direction! Thus, you can choose the form of settled snow.
Here's the example of windows desktop after some time of snowfall:
Download Interactive Desktop Snowfall for Windows XP, freeware, 800KB