You could use java script to detect if they have shockwave for flash installed or not and prompt them to load it. But the best you can do is aim them to the Macromedia site. Thats how Marcomedia gets all those numbers that they tout. And they use those numbers to make serious cash. Anyone installing the latest version of ie or netscape should be getting the lastest version of the flash plugin.
In the beginning the web was without shape and color, and the hype covered the darkness of the net. Then there was a Flash and life came to the web and vision became reality.