I have the following htaccess code:
RewriteEngine On
RewriteCond !{HTTPS} off
RewriteRule ^(.*)$ https://www.%{HTTP_HOST}%{RE
There are a lot of solutions out there. Here is a link to the apache wiki which deals with this issue directly.
http://wiki.apache.org/httpd/RewriteHTTPToHTTPS
RewriteEngine On
# This will enable the Rewrite capabilities
RewriteCond %{HTTPS} !=on
# This checks to make sure the connection is not already HTTPS
RewriteRule ^/?(.*) https://%{SERVER_NAME}/$1 [R,L]
# This rule will redirect users from their original location, to the same location but using HTTPS.
# i.e. http://www.example.com/foo/ to https://www.example.com/foo/
# The leading slash is made optional so that this will work either in httpd.conf
# or .htaccess context