Just in case this might be helpful to someone else, H.264 output from Sorenson Squeeze 5 for progressive download works without a problem if you choose one of the FastStart options. I uploaded a file to another server and it buffers for a short time and then plays. The problem on the first server was that the file would download completely before playing- too much wait time for the end user.
Going by a link sent by Daniel a few days ago, there are MIME settings on the server that must be configured for progressive download.
Does anyone have a recommendation for a company that provides space on a streaming server?
Adobe Certified Expert
Adobe Certified Instructor
Premiere Digital Video Editing