Thanks again for your answer bplex.

.htaccess is not enough protection for me. This is far from full proof and can be easily worked around if somebody wishes to use your bandwidth. I read that Flash Player (from 10 on) is now sending the http_referrer, as it didn't for a long time like most media players. But I'm pretty sure the headers can still be modified by the offending site. And this whole method is all quite loose. This is why I want to use vShare's temporary flv file links in the embed code. Any thoughts on doing this?