Protecting(Securing) Files with ASP.NET (using HttpHandler)

http://aspnet.4guysfromrolla.com/articles/020404-1.aspx
http://msdn.microsoft.com/en-us/library/f3ff8w4a(VS.71).aspx
http://www.gridviewguy.com/ArticleDetails.aspx?articleID=196 (downloads small chunks of large file)