Question about Flash Detection

Hey everyone, I’m sure I’ve put this in the wrong section of the forums, but hey.

I want to use flash on my site but am afraid people won’t have it etc.

I want a page which quickly checks if they have it, if they do they are taken to the actual page, if not it goes to a page telling them to install flash.

Now, that sounds easy enough, but is there a way that it won’t check next time? It’s just I can imagine it won’t exactly be a really quick check, so I don’t want my users to have go through it everytime they come to the site…