Detect crawlers redirect to HTML site?

Does anyone know of a nifty way to detect if Google or Yahoo, for instance, is trying to access your domain for indexing / search results?

I have both a Flash site and a HTML site but I don’t want people to arrive at the HTML site - this is mainly for search engines.
However, there’s that question again - what to do… ?

I was thinking it would be great if there was a script that could tell when a crawler was accessing the site so it skips past the Flash site and is still able to index the content of the HTML site…

My Flash site detects for Flash, then forwards to the HTML site (index.shtml) when it’s not detected. So, the first page is a flash detection script. Second page is the index.html (flash).

I know this is such a beaten down question, but I’m still searching for an answer… Even though Google says it can index Flash, it doesn’t do anyone any good yet, because you have to search using .swf !!! irrelevant at this point.

Anyone want to throw in their 2 cents worth? and perhaps a solution?