A customer recently called asking us to expand the timeout variable for downloading files via PHP from their server. By default the php.ini file does not exist in Mac OS X Server. If you need to use php.ini to granularly configure the parameters for PHP then you should download it from php.net by downloading the source code for PHP for the version that comes up when you run php -v from your server. In the tarball there will be a file called php.ini-recommended. Then copy this file to /etc/php.ini and modify the appropriate settings:
upload_max_filesize = whatever you want the new maximum to be
posters.max_execution_time = 30
max_input_time = 60
post_max_size = 32M
Also, there is sometimes a file in /etc called php.ini.default that can be copied and renamed for this purpose.