Seen this one before but while chatting with some (tech) friends I discovered most seemed to think that this should just work out of the box, well unfortunately it doesn't. But adding support on you windows driven website isn't that hard, just a few short steps. So I thought it might be useful to explain here:
You need to add the .flv MIME type to IIS:
First click on the site to configure in IIS, right click - select "Properties".
Under HTTP Headers Tab, select "File Types" button...