Here's a site that gives you tips and the tools you'd require. This site is designed to be non-intimidating shopping experienced for extremely nervous users. Check out the Matrimovie Cards in the 'pop the question' section. Very sparse but intelligent use of flash. Easy to navigate through the loads of information.
Flash animations are nothing more than eye candy, and ugly besides.
No business serious about making money uses Flash on their site. You need to go through a long download process to get the Flash runtime files. Anyone can build a flash animation - it's easy. This site is nice and simple and contains the excellent artwork of chas hodges. The original intent of this white paper was to provide Macromedia Flash developers with the knowledge necessary to create user-friendly Macromedia Flash experiences on the Web.