I'm now officially out of time. I'm not going to be at my computer the rest of the day and I'll be attending a symphony tonight. Monday will be the first business day of March, which means a lot of administrivia and phone calls for me. I'm sure the week will go downhill from there.
If you're still hanging around here, I'd recommend you consider Quicktime Pro for $29.99US to encode your video for progressive download. The MP4 format is an industry standard ... at least if was until Microsoft abandoned it. In any case, MP4 can be played by RealPlayer, Quicktime, and probably others. Most importantly, it's much less expensive to encode and requires only simple HTML to embed. Flash is not a bad choice, and nearly everyone can play it, but it's not generally used for trailers, because the quality is not as good as H.264.
You may even be able to embed your Divx movies, but I really know very little about Divx. Personally, I'd stay away from Windows Media, because Microsoft doesn't play well with others, and I try to resist their hegemony. You can let your own conscience be your guide there.
Doug