If someone comes to my page from http://mysite.com, is there anyway that i could have it reload the page with http://www.mysite.com ??

I have a downloads system which only lets people download from my domain, but it isn't very good in that they MUST come from www.mydomain.com and not http://mydomain.com.

try this in hour .htaccess file

Options +FollowSymlinks
RewriteEngine on
rewritecond %{http_host} ^domain.com [nc]
rewriterule ^(.*)$ http://www.domain.com/$1 [r=301,nc]

cool dude, it works, thanks.