If you're running Linux or BSD for your http server, you most likely already have the "wget" command. If not, or you're running windows, you can get it at
http://www.gnu.org/software/wget/wget.html
It's an awesome little utility that's designed for mirroring HTTP and FTP sites. I use it when I want to browse a site offline. Or I used to when I was running off of a 56K connection.