I think the benefit of using the boomers mod though is that it can be uploaded via the admin of x-cart (i don't know this as i havent purchased it yet so im just guessing here) rather than if the site is to be updated by a client who has no knowledge of ftp, html etc. but i suppose then the question is that if they don't know how to ftp then they arent going to know how to make a flash banner
So it think lildawgs answer is fine for doing things like banners but if you were going to use flash in a product item (i.e say you wanted 360 rotation of a product which loaded the jpgs externally) then the mod would be the way to go.