Apache and PHP came preinstalled on my Mandrake 9.0 installation, but now I would like to add a few more modules to php. How can this be done the simplest? Do you have to recompile the whole php source and install over the existing installation directory or can you just put some precompiled binaries in your modules directory and update your php.ini file? Thanks for your help.

Depends on your system as to whether it's an RPM install. I've never come across anyone using RPM PHP but they do exist.

The standard binary install will require a re configure and make, make install to get new modules.

Well I downloaded the source and reconfigured with the new modules I wanted, make, and make install, but the new modules do not show up as installed when running phpinfo();

did you restart apache?

yes, and rebooted

If you added it to the configure line then there is no reason it shouldn't be in PHP info (unless you have two instances of PHP installed for some reason).

If you rebuild from an existing local copy i.e. one you installed yourself and not pre-installed, you'll need to do a make clean first otherwise it won't recompile.