To use mod_proxy_html on OS X 10.6 Snow Leopard you can do this.

Download it from here.

Unpack it then run

$ sudo apxs -ci -I /usr/include/libxml2 mod_xml2enc.c
$ sudo apxs -ci -I /usr/include/libxml2 -I . mod_proxy_html.c

Then update you httpd.conf to include


LoadFile /usr/lib/libxml2.dylib
LoadModule proxy_html_module libexec/apache2/mod_proxy_html.so
LoadModule xml2enc_module libexec/apache2/mod_xml2enc.so


Also take a look at the proxy-httpd.conf file that ships with mod_proxy_html for additional config you may want.