An alternate way to handle gzip compression is to let the mod_gzip module of apache handle it. This seems to contradict the tutorial on phpbuilder.com saying that it won't compress php (or any dynamic) output, but mod_gzip as of version 1.3.17.1a works well for me.

Here is an example of an httpd.conf setup:

<IfModule mod_gzip.c>
mod_gzip_on                 Yes
mod_gzip_dechunk            Yes
mod_gzip_minimum_file_size  300
mod_gzip_maximum_file_size  0
mod_gzip_maximum_inmem_size 100000
mod_gzip_keep_workfiles     No
mod_gzip_temp_dir           /tmp
mod_gzip_item_include       file \.html$
mod_gzip_item_include       file \.jsp$
mod_gzip_item_include       file \.php$
mod_gzip_item_include       file \.pl$
mod_gzip_item_include       mime ^text/.*
mod_gzip_item_include       mime ^application/x-httpd-php
mod_gzip_item_include       mime ^httpd/unix-directory$
mod_gzip_item_include       handler ^perl-script$
mod_gzip_item_include       handler ^server-status$
mod_gzip_item_include       handler ^server-info$
mod_gzip_item_exclude       mime ^image/.*
</IfModule>

This will automatically compress all output of your files with the .php extention or the x-httpd-php mime type. Be sure to have dechunk set to Yes.